Braces, can be necessary for some mouth/teeth malformations.
Yes, it is being done, at earlier and earlier ages.
Some necessary, some just purely cosmetic and not required.
But, know that, teeth and the mouth, is not static. It is always moving and the jaw is growing etc. In kids, the mouth/jaw is not fully formed or grown. Yet. And their teeth are not fully, in. Their baby teeth and permanent teeth.
I had braces as a kid and had teeth pulled out for it. I had my braces for 3 years. Due to an undesirable bite and a crowded mouth.
But now as an adult, I STILL have to wear retainers... to keep my teeth in line. If I do not wear it, my teeth, moves. Back. Still. My Dentist said, that the mouth/teeth has "memory." It tries to go back to its original formation. So yes, a person STILL has to wear their retainers. Otherwise, their teeth, may get misaligned again, etc.
Which, is my situation.
So, I do not believe in braces per say, for minor issues. Because for me, well I STILL have to wear my retainers. Decades later. Otherwise, my teeth move.
But sure, my teeth are 'straight' now, cosmetically.