Crypto is yet to be identified by many nations across the world and is restricted by many. Most people , at least I can vouch for my network of crypto traders that they prefer to stay anonymous. Also, people stay in dark when dealing with crypto and share that with very few close people (Atleast I am like that). Plus, the hassle with KYC documentation and registration process could be a reason.
Simply because players dont want to know their identity, and since gambling is illegal in other country it is also the reason why many players dont want to be recognize or to know because having KYC in crypto player think it is something done by government which for me this KYC is possible made from government whi want to identify those people whi using crypto