>>537913986
There is no real validation, there's literally no way to interact with the other duelist.
A big part of it is liking the deck/card, you won't bother with something you don't care about, but it's also a way of expressing it to others.
In real life 99% of people don't know how to tell a Rolex from a 10$ AliExpress watch (That probably keeps better time than the Rolex), but since you like the brand and want others to appreciate your taste you buy them.
Also a lot of people have disposable income and can afford spending 50$ a month on a game they play daily for 8 years now.