I think casinos are starting to adopt KYC as a way of protecting their site from illegal activities or investment.
It's a mandate that they have to follow so they are passing the law to their gamblers. I'm curious how can they protect their site from illegal activity? what's the connection of KYC with it?
Since government saw the opportunity of using cryptos to hide money from corruption, sooner they will implement requiring of records from different exchanges as well as gambling site to prevent illegal activities.
This might be the reason but its hard to monitor on where the money on crypto is really coming from. You can't determine that it came from corruption or from a bad source.