I use bitsler for a long time and I have not provided any document to them. I have just filled the fields of name, email and mobile number. And withdraw a lots of time but still I have not faced any issue. I think they ask to provide document for specific case. I mean if they think there might have something wrong.
Ikr, and i've used bitsler too and never had any problem with that. But on that time i only playing on their dice games, boom and other games, not their sportbets yet. But filled the name , email and mobile number are also KYC imo.