Although casinos are banned in my place, I have never experienced a ban or difficulty disbursing Bitcoin to Fiat.
Everything went smoothly and was done easily without any indication.
But some people do say that they can't accept funds that are identified as gambling and such,
maybe the source of the funds is indeed prohibited and has had all kinds of problems, but so far I haven't gotten those problems.
And some exchanges also have certain rules about where the funds to be disbursed come from because they will be related to the regulations and rules that have been set,
This avoids the practice of money laundering that is rampant today.
One thing we must first understand about the characteristics of Bitcoin is that, it is fungible and the blockchain allows that every persons transaction is and can be traced.
This is also a reason why most funds from a casinos gets labeled or flagged as 'dirty' or 'tainted' because, the history of every transaction is permanently recorded on the blockchain and thus, gives room for specialized analytics firms to investigate and link every coins to the gambling activities it was originally from, and this is when such gets classified as 'dirty' or 'tainted' mostly if it is from illegal casinos known to launder money or banned in the region.