my reason only data security and complicated,
I don't gamble too often, so I don't feel I need a casino site that needs KYC,
there are now many good casino sites that don't require KYC,
so, don't mind the casino that requires KYC.
There are incidents that a non KYC casino would require you to pass it when you are about to withdraw. If they suspect you base on the history of your activity within their casino, they have the rights to do it.
I usually try to avoid KYC casinos, but there are sometimes require to have a process like this one.
There are a lot of people who abuse faucets and rewards which is a loss for the casino, so there should be some measurement that can eliminate those abuses.
And what's make it frustrating for a player? Is that there are casinos who would allow you to deposit first and then when it's time to withdraw, specially if you have big winnings, suddenly casinos will require you to send first KYC before you can withdraw evening.
And that's what disappoint most old school crypto gamblers. Because crypto casino's now tend to replicate a fiat online based casino. You have to undergo KYC and worst they will tell you that some suspicious activities can be flag in your account and unless you do full KYC you can't get anything, even the money that you have deposited on them.