This is from Wiza Jalakasi on Medium:

There is nowhere else in the world that moves more money on mobile phones than Sub-Saharan Africa

The region is currently responsible for an astonishing 45.6% of mobile money activity in the world — an estimate of at least $26.8 billion in transaction value in 2018 alone — this figure excludes bank operated solutions.

Mobile money operators like MTN, who also own the mobile network, typically charge in between 0.5–3% for their various digital services, a small price to pay for the convenience and luxury.

The whole thing is worth reading if you want to know about the current state (and future) of mobile money on the Continent.