Roblox is a platform where some users create games and other players play them. It’s grown to be a pretty powerful platform/engine, but is now significantly more complex than it used to.
Roblox has the ability for users to add micro-transactions to their game. Essentially, users get a small portion of the micro-transactions back as real-world currency. It’s up to users/developers who make those games to choose what players get in exchange for these micro-transactions.
As far as I can tell, the quality of games has dramatically increased since I quit. My guess would be that the users/developers making games are now adults, and the players are still kids.