buying fancy clothes is like buying fancy kits/parts for your car. its a hobby and makes it looks good.
you dont have to do it and you can see of it as a waste of money, but to some people it isnt
there are plenty of hobbies that make me think like why would you waste money on that, like anything related to RC vehicles imo. but im not going on a rant by how expensive those things are and why people would buy that.
some people have a big garage, some people have a big closet, for example, it's just another hobby, and it's all expensive. because hobbyists care for their hobby and want to go in-depth. no RC hobbyist would just take the cheapest RC car and call it a day. No fashion hobbyist would buy skechers and call it a day.
when it comes to what makes people happy you should keep an open mind. when they buy those 350$ shoes, they might just feel the same as you installing that new 350$ graphics card into your system. (as example, not an attempt to generalize)