I cant give you correct answer on that, but there are some casinos, where I cant open slots from some providers, and sports betting are also restricted for my IP. However same slot easily opens in other casinos, as well as sports prediction. For example I cant access sports betting on stake and betfury, but can open it on earnbet and duelbits. All the Hacksaw gaming slots for some reason are restricted for me in any casino. In some casinos even Pragmatic slots refuse to open. I cant explain why this is so selective. But, I have accounts in all that casinos and my country is not restricted. The way I get it, VPN that Bitz advertise only open access to all gambling games, but casino still dont allow users from restricted countries to have an account.
In that case, Bitz is probably aware that it's more like a technical restriction or bug, not something directly related to a country's law. So if they themselves allow users to use a VPN to access the games, then I don't see much problem with it.
After all, the casino is still the one responsible for the account and payments, while the game providers are mainly just supplying the games. So I guess that's the simple way to look at it. I wouldn't overthink it too much, as long as the casino itself is giving users a solution to access the games, then that's already a good sign.