not all of them(all country in africa) are so advanced and are confortable to use technology device, this is true for the sud africa, nor africa on the other hand is getting better, and they have nothing to envy to europe or usa(i have friend that live there, so i know a bit about it)
Some 90% of the Africans live in poverty. But at the same time, there is a large community of the African nouveau riche, comprising of businessmen and migrants who have found jobs in the EU and North America. There are tens, if not hundreds of millions of people who use smartphones in the African continent. It will be foolish to ignore this large group.