Oh, I wouldn't say that art educations are useless. I think a lot of artists do benefit from them, and in very rare cases a company might prefer an artist with a degree over an artist without one, but the answer to the question "Do you need a degree to be a successful artist?" is quite simply "No.". 

Jobs for larger companies do usually require that you have some experience in the field, but in the end what matters most is the quality of your work and how easy you are to work with.

Not entirely, from what I hear a good art school (one where teachers actually have industry experience) is helpful in many ways - the diploma just isn't one of them. And your bank account isn't either, they're generally pretty expensive, and so are plenty of the not-so-great schools. If you can afford it though, I've heard many people recommend school, if only for the networking opportunity. It's hard to get really qualified critique outside of a school setting, and you'll improve much faster with good feedback. A good school also pushes you harder than you'd probably be able to push yourself. It depends on your personality a bit, some people learn great on their own, others do better with instruction and structure. And being surrounded by likeminded people is a boost to inspiration and motivation as well, one that most artists aren't lucky enough to experience without going to school. Everything has its pros and cons, I guess. But yeah, if there's any job you don't need a diploma for, it's this one.