I'm very sure that casinos use IP addresses to customize the layout and most especially  fiat currency for their users however what I am not sure of is if there are some games on some casinos that are tired to a particular region. Games that most people like on casinos are almost similar and making it accessible to only one region in particular may hinder people that like that game from gambling with them.

Aside from that, if it's a saud decentralized casino then trying to collect user data without their consent won't go well at all.