If the government legalized crypto currency in the country, of course the possibility of crypto being one of the payments for physical casinos could happen, but of course users would prefer to use fiat currency when playing at physical casinos because it is more practical in nature, except for gamblers, who have a lot of capital, of course, it will be very risky to bring a lot of money so maybe they will prefer to use crypto currency later.
No matter what circumstances may be, it is always a bad idea to run around with pockets full of cash. That is why most gamblers carry their credit/debit cards instead and usually prefer to use ATMs before the actual game. As saying goes, when it comes to gambling cash is a king. However, cryptocurrency can also be withdrawn via crypto ATMs, so I don't see any problem if there is a place nearby where I can quickly exchange my crypto.
It's more easy to bring your card and withdraw to an ATM nearby than bringing your wallets that full of cash. There are gamblers who also have credits those VIPs which can play without bringing out anything.
And with that argument above, crypto, once being recognized by the government, more businesses will cater it and adopt the system.
It's easier to withdraw your money if you understand how crypto works. You can simply go bringing nothing out from the casino, aside from the withdraw crypto though: