The kyc is due to the casinos license. Otherwise Bitsler and every other site out there asking for it would not be asking for it. They have rules they have to follow unless they'd rather shut down.
If the information I got over the ENG chat is accurate, a simplier profile verification/identification is good enough for most 3rd party provided games.
Maybe because if you edit your personal information onsite, it would already include the state/country, so no neeed for i.d. uploads and selfies.