Well, many people have already proven they can develop successful games without an education like that. However, it all depends on what kind of person you are. Are you someone who needs structure or needs motivation from others? Then a game design education could be an option because it would provide you that structure. Furthermore, you'll have interesting like-minded people to talk with. However, in my opinion 99% of what is taught in those classes can be learned from online tutorials and online community interactions as well. If you learn best by being your own teacher then you might not need such an education
Hope it helps!