I think some casino places have started migrating to online platforms because in offline places where their casinos are quiet affected by this virus outbreak, many people prefer to stay at home, while all over the world I believe everyone already has internet access so when they want to gamble it is easier to use the online system.
And some other casinos remain to run and open their physical casinos. That is because they couldn't wait a little longer for the curve to flatten. And also, the development of a gambling site could take a month to finish as they need to beta test its feature especially to match the platform to their physical casino.
With regards to alternative casinos such as those that are online, I advise that they should use provably fair casinos to ensure fairness and they could verify their bet's outcome.