If you're a person who lives in Tanzania and is considering getting into mobile app development — and you've decided, first-and-foremost, that you want to "work locally" to produce apps that benefit your fellow Tanzanians — then by making this decision, you've basically opted out of "selling apps" altogether, instead placing yourself firmly in the "selling app-dev labor for the development of free apps" camp; and you've also opted out of targeting iOS, since it's got at most 7.75%[1] market share in Tanzania.

(And probably a large percentage of that 7.75% is tourists visiting for safaris, who won't ever be downloading your app-for-locals anyway. Tanzania's less-tourist-inclined neighbour, Kenya, has a 3.43% iOS market-share, which sounds closer to realistic for the area.)

[1] https://worldpopulationreview.com/country-rankings/iphone-ma...