This is one area that Bill Gates has mentioned Crypto can actually benefit.
Well if they're not unbanked by choice, chances are they don't have the means to afford electronic devices let alone internet/data. The fact that Bitcoin is dependent on technology definitely makes it harder for poorer countries to really embrace it.
Also, feature phones without the ability to install apps are more common than smart phones in poor countries so something like Bitcoin payments via SMS would be easier to integrate into the existing infrastructure I think.
You are right, money transfers would be very a great help not only on transfer time but also on saving up money regarding transfer fee compared to other money transfers.
Bitcoin could really help poor countries especially to those who are jobless since bitcoin could give you earning opportunities that could somehow makes money for them.