Thats true, having a license doesnt guarantee that the casino is not scam and can be trusted in the long run because this still depends on the casino's build reputation and it really takes time. Roobet is one of the trusted casino existing nowadays and I bet we are aware of their reputation here and outside. They're consistent with their marketing strategy and promotions and if there's an issue they are fast to resolve it. Plus their support is online often if there's an issues which I like the most.
I have no idea about license of gambling but there are a lot of business who opens their busienss first and then try to take licence and also on several business licence cant not be approved for several months/years but it doesn't affect too much on their business. It may happen for gambling too.