I never knew that someone can use casino to hide the origin of fund. Although if not for a bad intention of a case of stolen fund or hacked fund I don't see any reason why someone would want to go through that process why there are just simply ways to send fund and trade through P2P and cashout your bulks. But any way whatever has disadvantages also have advantage meaning it can be used to keep fund safe from hackers or people who might be tracing someones fund so with this process the destination will be cut short along the way. Thereby bridging the tace.
Yes, they can hid the origin of fund in many places including in casinos because other people will not knows what they do except casino. Casino will asks us to explain where the funds come from and that's why casino will asks their members to do KYC especially if casino finds something suspicious from their members.
There will be someone used casino or other business to hide the origin of the fund from the authorities. Those people use illegal ways to make money and they wants to hide that from the authorities so they will search for a way to makes their activity difficult to finds by the authorities. Those who hide the origin of funds will trying many ways to make sure their secret will be safe from the authorities so they use casinos to hide it. That will makes authorities difficult to track the origin of funds especially if casinos is not report the suspicious activity in their place.