The casino does not ask KYC at the time of registration is to avoid new users from running to another casino because it is already faced with choices that are not liked because KYC is not something that players like even though this is no longer avoided.
And asking KYC when withdrawal of course there is a reason usually when the casino detects suspicious activities, but the reason is still unpleasant for the players and I have experienced this sometimes, and when asking the reason it was said because it detected suspicious things even though I only did normal, and What is more unpleasant sometimes casinos cannot answer the real reasons from the necessity of KYC to withdraw funds.
But do you know that in normal circumstances as a gambler you have to do your kyc verification in gambling before any other things, even though they have not ask you to verify your account, I think it's better for you to verify because if they have not asked you do so, during the time of withdrawal they definitely ask you to do your kyc verification, so I do believe that kyc verification is necessary and needful at the early time so that you will not find it difficult to run your verification when is needful, some people does not like to review their document but when they win a large amount in casino they input their document that is on secret in order to cash out their funds