Blaming Covid for the reason the admin can not get a license will not be good because if he works with some people, he can delegate them to do what is necessary, so at least, the team can try to get a license and make their site legal. If they can not do or can not get the license, they will lose what they build, especially their members. The reason for the casino closing down is not clear, so we do not have to follow them again, and we can use the other gambling site to playing gambling.
That's why it is better not to stock money in gambling site, it may cause us transaction fees but it will keep us save in instances like this. As much as possible better to play in casinos whose already built their reputation and scared to lose it, we will know it by how the team respond in our queries and how fast they can solve some issues.
We can store our money in the gambling site, just in case to reduce the transaction fees, but we need to have control ourselves because that can make us feel that we have money to gamble anytime. If we lose control, we can use that money to play more and more without stopping, and in the end, we will lose that money. If we want to do that, we better select the casino with reputations as you said, so we do not have to worry if they will scam us.
Yes storing funds on gambling sites allows to reduce transaction fees but more importantly it avoids having to wait for hours the mining of your transaction. When you want to gamble on a specific event it can be critical. Currently the BTC mempool is extremely high, so it's almost impossible to send BTCs in less than one hour if you can't pay unaffordable fees. That's why it's important to only choose renowned casinos like Stake for example.