Hm... when you put it that way with the maximum bet limit I think you're right. Very low chance of a casino going bust unless they get cheated or hacked. That does seem like the biggest risk...it happens to even large exchanges and casinos online as well as in real life so that's a decently big risk imo.
Yes hacks are the biggest danger a casino could face.
But most of them are already storing 95% of their funds in cold storages or multisig wallets.
They can easily calculate how much
BTC the casino pays to gamblers daily and only keep that much in the hotwallet, the rest can be kept safely in a cold wallet and only recharge the hotwallet when it's needed.
So if a hack happens they can only steal 5%, which is still bad, but better than 100%.