I realize that Africa is an enormous continent; I'm just curious if this doesn't also help out developers and startups in places like Nigeria...? I don't have a sense of the topology of the Internet throughout Africa vs particular African nations and the rest of the world.
I linked to it in this comment https://news.ycombinator.com/item?id=18300309
The backbone cables loop around the coast of Africa. Cape Town is on that coast. So is Lagos, the most populous city in Nigeria, the most populous country. But the most populous area and economic hub of South Africa is around Johannesburg, which is far from the coast.
We assume that AWS took the decision that the South African economy today was more important than the Nigerian economy; this data centre won't be much closer to Nigeria than European data centres are. Or maybe the double distance, double lag time at South Africa is a bigger reduction to eliminate.
This press release https://www.allthingsdistributed.com/2018/10/an-aws-region-i... says "The new AWS Africa (Cape Town) Region will ... provide lower latency to end users across Sub-Saharan Africa" We can assume that this statement is truer the further south of the Sahara you go ;)