If any other country does not follow bitcoin which I know its impossible, those two countries are definitely keen on finding out what will happen or happening in the crypto world with bitcoin taking the lead role and that is why some exchange sites and gambling sites specifically banned users from these two countries from patronising their services.
Which services are banned for UK citizens?
There are loads of services not available to US citizens, not just crypto services. It's because their rules make it a real ball ache with paper work etc. That's its not worth the agro. And online gambling is illegal for US citizens