You can assume that in principle every gambling site will eventually start talking about kyc. The reason for this is then actually unknown. It can be used to delay payouts, but they may also have to adhere to legal guidelines.
Well, if it legal requirement they can certainly make it clear. Atm it seems rather abrupt. I searched on the forum, and found quite some instances where high payout went into pending status until kyc was completed.
I saw their 0 house edge promo, so had to make a post and confirm.
Personally, I am not a fan on kyc policy. So I usually avoid those crypto books.