I mean technically speaking, if they were playing on crypto casinos then they're bound to know about how crypto works, so they should be able to buy their own via exchanges if need be, and not directly with casinos themselves. I don't think it's going to be "that" much of a big thing, for all we know they may have stopped said services exactly because of that, that their customers don't really use the service and they're basically losing money implementing said services.

As I said, I don't think it matters much, it's not like buying in exchanges is that much of a pain in the ass, except for KYC for the most part I guess.