I will start with one to begin the discussion. If you are putting huge amounts at stake and want to keep identity private, online gamblign comes as a boon.
But there are instances on where you do really need to pass up KYC for some gambling sites when we are already talking about big amounts. Depositing might not be a problem or would like a breeze but when you are already withdrawing then expect problems would possibly faced on these times. Im sure that most gamblers do knows about this. The thing we do like is anonymity but instances of KYC has a chance for you to comply on some situations.
I have never really been on any site that has required KYC anyway, but assuming there are some like you have mentioned, then I really do not see any point for the KYC, unless the gambling platform is registered under a country with a huge gambling policy which makes it very important to conduct.
For most of the platforms, this is not the case and this has really helped the platforms to grow hugely over the years based on the fact that you can easily do your thing without being spotted and get paid without any issues from the bank or government.