There are alternative ways to deal with this situation. Many casino sites have different kind of payment method which includes alternative coins. It is not necessary that you only use Bitcoin for your transactions. You can simply use other coins until this congestion get cleared. The recent transaction fee is quite low compared to some days ago. But it doesn't matter when you have alternative ways to deal with such situation.
In times of problems you can use alternative ways and that is why alternative coins were created. Go take advantage of that. It will be much easier faster and cheaper.
It's low now because the people behind the exploiting has give it a break. Wait for a month before halving and see some crazy fees around Bitcoin transaction. As long as inscription exploitation of sats on Bitcoin network bug is not fix,the crazy transaction fees aren't going anywhere, it will resume and miners will be the only people enjoying this fees because people have bitcoin to spend and wouldn't sit and allow their investment to decline.
The alternatives is are good in funding Casino but the challenges here is that people want to see their win in bitcoin. For instance, if you deposit USDT using Tron(trc20) as people are suggesting, if you want to wager, you have to wager with the amount you deposited but for casinos that has market place where you can trade, you can move your coins from casino wallet to the market place and do some trade in the casino and then move back your coins the casino wallet where you can bet using bitcoin since many people prefer to use Bitcoin to gamble and have their profits in Bitcoin.
Another challenge could be because altcoins can be seize, we have seen so many instances where USDT are seize by the company, you don't want your profits be seize by one company because they suspect your money or doesn't like the casino you use for betting, there are the problems of the alternatives.