In addition, do not forget about the execution time - usually casinos require several confirmations, and I think that in modern conditions it is irrelevant to wait for a transaction to be completed for almost an hour.
Afaik most casinos only require one confirmation on bitcoin deposits and sometimes there are other casinos that require a few more for withdrawal requests.
I rarely play with altcoins but I think they're the ones that require several confirmations since the block times are much faster.