And even if they do use BTC (they don't really, at least in Africa, i don't know about Venezuela), they do not trade using BTC but a second layer anyway.
Is it the shitcoin or is it the fact that the economy itself is gone and thus your currency isn't worth anything because nobody is selling things to you?
It isn't necessarily "Africa" or "Americas".
The heuristic is "is my local fiat shitcoin stealing my purchasing power".
Counter to your claim and easily provable with a basic search Nigeria is one of, if not the leading in BTC adoption %.
https://www.msn.com/en-us/money/news/nigeria-is-the-second-l...
https://www.statista.com/statistics/1194735/bitcoin-online-s...