>over $25B in value was transferred with it last year
...Which is attributed to being the first-to-market payment system for Kenya, as the person before you was describing. U.S. and Kenya merchant markets are still an apples to oranges comparison.
Sending and receiving "money" within the same network is fairly trivial from a technological point of view but once you tell customers that it is "money" that they can technically convert to and from cash, I imagine there are significant bureaucratic hoops to jump through, at least in the US. I bet even something as seemingly simple as Chase QuickPay is actually pretty complicated to implement (step one probably being: be a bank)
...Which is attributed to being the first-to-market payment system for Kenya, as the person before you was describing. U.S. and Kenya merchant markets are still an apples to oranges comparison.