Though we are lucky because our government isn't having us banned or restricted but for those who lives in restricted countries they have no choice but to use VPN but better to use those paid and not the free one.
But if you are using it from restricted region then you are directly violating the terms of casino as they have mentioned those regions so it's until then when you are not caught because casino wouldn't allow players to gamble using VPN in that case.
It has been mentioned before here, but don’t use a VPN if your country is on the restricted list. Duelbits accepts the use of a VPN to bypass some of their casino games so you can always play your favorite slot but only use a premium vpn as free ones will cause issues.
That's the difference case if you are trying to playing some slot through VPN because you are not restricted to play over casino so you can bypass it and duelbits themselves allow it as you say so it's not a problem but with other restrictions it's a problem.