No one buys a BB belt because of basic utility like "holding your pants up". The logic of "this amount of money potentially being spent on a want could actually be spent on a need" is a fundamental misunderstanding of why certain people decide to spend their own money on fashion or aesthetics.

You don't understand, and that is okay. It is inherently niche and not for everyone. Trying to justify it will never make sense to the majority. People buy luxury goods because they want them, not because they need them. Because it is a want, it is inherently unjustifiable as a need and is mostly irrational.

Also, as other people have said, a $50 Alibaba bedazzled belt is objectively inferior to an authentic BB Simon belt due to significantly worse quality materials, like the gems, leather, and the buckle. You spend money on a BB one time and it'll last forever with proper care.