You're simultaneously underestimating how sophisticated the existing telecommunications ecosystems are in developing nations and overestimating their reliability.
There is, has been, and will continue to be a veritable mini-industry of everything from http://textit.in/ to https://en.wikipedia.org/wiki/M-Pesa . In many senses developing nations are actually ahead of the curve, especially when it comes to mobile banking.
FFOS is a solution in search of problems, unfortunately those are problems which already have better solutions.
There is, has been, and will continue to be a veritable mini-industry of everything from http://textit.in/ to https://en.wikipedia.org/wiki/M-Pesa . In many senses developing nations are actually ahead of the curve, especially when it comes to mobile banking.
FFOS is a solution in search of problems, unfortunately those are problems which already have better solutions.