Braces straighten your teeth and make you look better, yes, but they also serve a functional purpose. It makes it easier to chew food, clean your teeth, your teeth will wear more evenly, and also it can help prevent sleep apnea as you get older.
Do you really think so many parents would shell out thousands of dollars just to make their kids look better? If that were the case, more parents would just get their kids nose jobs and breast implants. Plus, they would also make it the child's decision if it were just cosmetic. And how many people would go through all that pain? Not many (or as many, anyway).
I hope that clears things up.
