If you cash out by bitcoins at a casino and the casino doesn't add enough fees for fast confirmation. If the price of bitcoin drops a lot. Should the casino be held responsible for the price differences in which you cashed out at and the current loss in btc prices?
If you bet in USD or in your local currency, you should be able to withdraw in Fiat. But if you gambled with btc, I don't see why the btc exchange rate is a problem, so far as you received your payment.
In the other hand if you feel the casino isn't paying out in a timely manner due to low fees, it is best to move your gambling elsewhere. Or make it known to them you would leave if they don't step up. Some casinos listen.