KYC is implemented to ensure that all who would use the platform are of legal age, and avoid money laundering or any other illicit activities. It's part of their compliance to be able to operate while abiding by laws and regulations required by the government. It's normal for anyone to undergo KYC if a huge amount of money is involved to ensure that the casino will not be used in illicit activities. We can't deny that there are a lot of people who uses crypto to abuse being anonymous, but crypto casinos operates in accordance to law same as an offline casino.
And it could really be the norm moving forward, crypto based casinos are going to ask for KYC to verify everything is not a missed specially if you win huge amount of money.
Although myself? I haven't asked to go to a KYC because I haven't been winning big in the thousands of dollars but in any case, I don't have a choice and will go to the mandated KYC to withdraw my winnings.