So having a cold wallet for a casino is recommended because that can prevent hacking that can happen anytime.
Cold wallets has nothing to do for security of the gambling website to prevent the hacking.
If you mean it's used to minimize the damage of lost funds taken when a hack happens, then it's reasonable.
In any way, gambling websites should have the same security feature of what exchanges do, it may be a matter of # of funds stored in its hot wallet but it is still a fund to run the business and should be considered in high level of security.
Cold wallet is just a back-up plan and it can’t really prevent hackers, better to improve the whole system and increase the security on every account to avoid any big losses in the future.
I believe on exchanges security are doing great but I think gambling site can so better than them since there’s also a big money in gambling, they should invest more on their security so gamblers will have a peace of mind trusting that specific site.
There are still gambling sites who do only refill out their hotwallets if needed and most of the funds been accumulated or stored would be on their cold wallets yet its true that
gambling sites and exchangers are really that like honeypots for hackers yet this one involves millions of dollars which they could possibly stole.So far there were no huge breach
or exploits happen on gambling sites but we've seen some in the past which do proves out that its possible to be done and having those losses.So only
deposit on the amount which you can afford to lose as a user.