Do not forget that KYC is a way to prevent fraud. No person who has passed KYC will cheat. Another thing is that the casino must provide such conditions that it is impossible to purchase other people's accounts with KYC or pass fake KYC. If casino conducts KYC, then everything should be as honest as possible.
If a person wants to commit fraud and knows in advance that he will commit it, then he will find ways to avoid KYC, if he does not find such ways, then he will go to another casino where KYC is not so hard or there is no KYC at all.
Not only that, scammers offer to buy accounts which have passed KYC already to perform their scams and people thinking they can make some easy money sell their accounts to those scammers, and then they are the ones that have to face the consequence of whatever the scammers did, and while this may seem like one of those things that would never happen it is quite common as I have seen several offers like that in the past in this forum and most likely a few users decided to sell their accounts to them.