Yes it is definitely only possible for small gamblers to use casino sites without kyc. Because without kyc very big transaction limit is not given which is why KYC is mandatory for big gamblers and big amount transactions and bets. And if they don't do KYC any time they may face problem and in that case their money will be at risk. So big gamblers must kyc because if they Don't do that. it will put their money at high risk
Any big win always requires passing KYC in a casino with a license, and if you play in a casino without a license, you will never get your big win. The casino simply won't pay you the money.
Every casino site has their rules and regulations written about everything like withdrawal limit without Kyc, deposit limit, bet limit, winning limit etc. And it is mandatory for every casino site that if one wants to gamble with big amount then he must complete KYC there. Because all the licensed casino sites always keep a small limit for their customers without kyc because if high limit is given without kyc, the criminal activities like money laundering will increase a lot.