I don't see why bitcoin would be widely used there yet. The MPisa service already seems to give the ability for individuals to transfer money between themselves within the country, and it is probably more expensive to use bitcoin rather than Western Union to transfer money into the country because of the fees, inconvenience and risk currently associated with buying and selling bitcoins.

I think these fees, inconvenience and risk for conversion betweeen bitcoin and fiat are possibly the most important indicator of the viability of the bitcoin economy, and I'd love to quantify them in different countries, and track them over time. Specifically, I'm interested in the percentage cost to transfer fiat to bitcoin and bad again to fiat.

Think about how hard it is explaining bitcoin to an average American who has access to 1st world services, internet etc. Now think of how hard that would be to explain to someone who has no concept of what the internet is.