I am always amazed that sites always indicate that games are provably fair. The only fair games out there are those from a recognized software provider.
Those simple games are well programmed, but I have serious doubts about their fairness. Do they have certificates?
If they arent fair they wont really be showing up something about their fairness which you can find it here:
https://bitdouble.io/pf.phpThere are sites that had some verifier and had mostly compiled most famous crypto online casinos at the moment:
https://www.btcgosu.com/tools/provably-fair-verifier/