Going to a bank requires a drive of 4 hours with public transport in El Salvador and is one of the many issues for rural areas.

But yeah, eg. Africa uses sms for lending and transferring money. Which is also perfectly fine and it works there.

Lookup 'mobile payment banking' and it works there, even with corrupt governements.

( I'm not saying the situation is perfect. But for access to money, borrowing, saving and banking, it's a solution)