The short answer is: Yes, there is a point. In fact, if you want to make a carreer out of art, or design, you must go to art school. You can dispense from it if one of the following applies to you:
You're a genius in your chosen field. You have an innate grasp of art/design principles and the ability to impose your ideas in the field so that you don't even need to learn the nitty-gritty. Unlikely, or you'd be famous by now.
You need a formation but you have the vision and discipline necessary to get one as complete as a school would provide on your own. If that were the case however, you certainly wouldn't be asking The Question.
You have no intention of making a carreer out of art or design but just want to dabble with either on the side.
If you recognise yourself in one of the above (without lying to yourself; "my friends say I draw amazing fan art without having learned how" or "I know where to look for tutorials" certainly don't qualify), no need to read on.
Now here are reasons why you should go if you're serious about art. Notice "getting a degree" is not even on the list.
Is it actually possible to believe that people get a higher education just to get a piece of paper that says they know something they could have learned on their own? What kind of hippie reactionism is that? We go to school to learn, people, not because someone is forcing us to, but because we care about our field, want to know everything we can about it, and actually improve in it! Here are a few things about learning:
There is a lot to learn, about many media and within each medium, conceptually and technically. And no better place to find it all concentrated than a good art/design school.
You will never learn as much on your own as you will learn in school. Never. You are one brain where school offers you many, and you only have one life where school allows you start from the sum of knowledge amassed by many masters over many lives. If you insist on spending 10 years learning something you could have learned in one course in school, that's your funeral. Other people are more interested in exploring something new than in reinventing the wheel.
Moreover, and I see this in every amateur on this site and elsewhere, in every first year student: you have no idea how little you know until you enter the major. So it's not like you can look up everything on your own: there are things you don't even know you should look up. You wouldn't question the necessity to go to engineering school, yet you can find written material about every aspect of it. Not so with the arts, where much of the teaching is subtle and can be only transmitted indirectly (you can't be taught to design, you can only be guided towards it). Yet you don't think a structured training is necessary for a discipline that can't be pinned on paper?
In school you do not only learn. You become. The curriculum deconstructs the way you think and reconstructs your mind for the purpose of art. That is what sets a professional apart from an amateur. An amateur will always be "doing art". A professional is hardwired for it. It's not something you can even comprehend until you've been through it. That's what a formation is about.
Discipline is not self-imposed. It must be imposed from the outside. You'd have to be exceptionally iron-willed to put yourself through what we go through in school: the endless readings, the tight deadlines, the projects you really don't feel like working on, the redos that drive you nuts, the competition, the overnights, the imposed subjects, etc. I don't think it's humanly possible. I'm extremely disciplined and driven, yet after I graduated, and despite really wanting to, I never once re-read the school notes I had promised myself to read. And so one misses out. Self-taught people have the natural tendency to go straight for what they want to learn. They don't take sidetrips. But it is the sidetrips that feed your skill and give you an edge. An elective in psychology for instance can inject wonders into your work.
I see some very skilled self-taught artists with one large weakness that betrays the fact they received no education: they can only do one thing. They have one style, one medium. They may be very good but it gets boring for everyone, it gets outfashioned quickly, and it's a dangerous situation on a professional level. An art career, or a freelance design career, is a gamble: you make it safer by being versatile and able to answer any commission. Such versatility comes from being forced to do things you would not choose to do on your own, and exposed to ideas you would normally not be interested in. Think about it next time you turn up your nose at a teacher that forces you to step away from your cherished style...
If you think getting feedback on dA helps you improve, imagine getting monitored and mentored daily by experienced, active professionals who can spot your weaknesses and know how to make you work through them. People who can evaluate your work not based on personal preference, nor even solely against a set of art principles, but in the context of the past and current art scene. Who can train your mind alongside your skills and show you how to marry concept and execution. Whose contacts in the real world can take you far. Who can force you to create a future for yourself with your skills instead of wasting them on something that will never get you anywhere in life. Or did you really think college teachers are just fossils that they keep around to keep anime drawers out?
Taking classes implies classmates. Setting aside how much more fun it is when you have road companions, think of them as extensions to your creativity. They are the ones who will come up with stuff you would never have thought of, and vice-versa. They're the ones who will look at your work and, empowered by their intimate acquaintance with it (after the first couple of years, you'll be able to spot each other's style a mile off, for life), suggest fixes or give you wild ideas, to complement the more realistic approach of the teachers. They're the ones who make the learning and experimenting fun and the worst chores (like creating a Munsell solid) bearable. You will learn from their mistakes and from their successes, and you can experiment on them, as well as enroll their help when in dire need of extra arms.
During your scholarship, you will participate in workshops, attend lectures, go on field trips, be sent on internships, enter department-wide or nationwide competitions, meet professionals, handle small freelance jobs. By the time you graduate, you will have a foot in design circles, a useful list of connections, and enough professionals should have heard your name to give you a start in your career. People in art school typically don't have to worry about ending up jobless.
Potential employers rarely ask to see a degree. They prick up their ears, though, at the mention of your school, especially if it's a reputable one. Here's what the fact you graduated from art school tells them on the spot:
Your skills have been tested and recognised by art professionals, who will vouch for you upon request.
You are familiar with the workings of the system and the details it is your job to know.
You can make a deadline.
You can work under pressure.
You have professional standards for quality and pricing.
You can do the best job for them their money can buy
And so on.
Someone without an official education is at a disadvantage, because no client wants to invest time into verifying all the above about you, as they would have to do since nobody else can vouch for you (unless you come in with a letter of recommendation from someone reputable, but how are you going to reach such a person in the first place if you're not introduced by the school body?) An amazing portfolio may not be enough, because the other factors (speed, reliability etc) are just as important. They may choose to take the chance, but they won't pay you the same. Very few people will pay professional rates to someone untrained, because for that amount of money they can hire someone with much more credibility. See the catch? You may end up spending your life doing mediocre jobs for cheap clients. Your chances of breaking into the higher circles, where the best in art and design take place, are slim at best if you're on your own.
Where else are you going to be able to experiment with so many media without spending a fortune? Our design (not even art) department put at our disposal, to name a few, work spaces, fully equipped etching and silkscreen rooms, a photo lab, a computer lab, projectors, digital cameras when they were not so readily available, and, of course, an enormous library. We also got student discounts on art supplies and printing services.
I can think of more, but 7 is a good number to end at.
In conclusion, here's a suggestion to those who seek advice on the forums: Don't. When something may potentially determine your path in life, you should ask only people you can trust. People who have been there and can respond based on solid personal experience. I see too many deviants responding with the completely cliché and shallow "you don't need a degree,all that matters is your skill" while they are not even of age to go to art school yet. Do you look up the info of those who give you such advice, to make sure they are actually over 13 and have a clue what they're saying? You should. As for the advice-givers: unless you are an art student with some insights to share, or better yet a successful professional with solid arguments to contribute on either side, show some responsibility and abstain. Whether you're well-meaning and naive or plain arrogant, you are causing more harm than good.