People are very sensitive when it comes to matters related to money, and this is even more true on this industry, in which a small delay can be interpreted by some gamblers as a reluctance by the casino to pay to their gamblers what they are owed.
So fast and reliable withdrawals are at the very top of the characteristics a casino must have in order to have any chance to become successful, as a casino that failed in this aspect will soon find itself facing huge difficulties to attract new gamblers.
It shows how people value money so much but I can not blame them for that because I know that money is hard to find. Gambling is risky so a gambler is happy once they win and they are now excited to hold that money on their hands. Another risk is if the casino is a scam and will not process their payment.
I wouldn't mind a small delay because that is normal as the network can sometimes be congested. I will only be alarmed if the payments are not processed for a couple of hours if the site promise instant withdrawals. There is more than the fast withdrawal if a casino wants to be successful so they must work their other features too.