That said, I really don't like how casinos like this handle it. Especially the "You may continue playing while you wait" is a little predatory. I've long suspected some casinos have intentionally done this sort of stuff to encourage people to gamble (i.e. i've seen some casinos where they ask large winners to wait >2 days+ etc). I think the best way to handle an empty hot wallet is to queue any withdrawal that couldn't be processed (and deduct the amount from the persons balance, so they don't gamble it). And of course, any serious casino should be able to process almost every single withdrawal without delay.
Sorry for your loss though,