Are you implying that because someone lives in an oppressive country that they have no money to transact? I really dont understand your question.

Oppressive regimes tend to control money flow in/out of the country. So if you, for example, have an aunt somewhere outside that wants to send you money -> you just might not be able to receive it, or would need to give some official a slice of the pie. Bitcoin obviously can help as u can just move the money without government oversight.