Why would you even play at such a casino?
Most of us if not all prefer instant withdrawal ofcourse. But there are still some online casinos that manually process their users withdrawal. Playing in on an online casino is matter of trust, i would rather play on one that manually process withdrawal but im sure that my withdrawal will push through.
I will certainly not play again on the site whom withdrawal are delayed by more than 24 hours. Some sites do process manual payments but they should not exceed a day. Instant withdraw are the best but there should be some check and balance. If there is a lot of withdrawal at a certain time, bots should detect and stop all withdrawals as this can be a hacking attempt too.