Stupid decision for high rollers to avoid KYC compliance casino since this could make them more secured especially when dealing on their accounts and transactions happening there, hackers cannot easily withdraw especially with huge amount of money since for sure they will be flagged and ask for KYC for verification.
Compare to Non Kyc casino where hackers can easily take out their balance and worse the casino where they trust is a scam and they cannot withdraw their money deposited on scam casino.
In the casino without licence the rights of players are not protected at all. The owners of such casinos can close them any time they want taking the money of the users. It is so simple to open new casino and do not pay players at all.
KYC is good but there are some casinos that bypass it because of it cumbersome nature of registration, and they are doing well in the online casinos platforms. Though it is not encourage to register to a casino site that has no KYC or license because you the gambler is putting yourself in danger, anything can happen along the long run. So you are advise to deposit what you can loss and it will not pain you if it happens. KYC protect the interest of the play and the account as well. So it is better you use a casino that has KYC and fully registered.