Because somehow for them, USD is still not good.
And most of people are afraid on USD because not unlike with Bitcoin, Bitcoin got only limited supply, which is 21 million.
The price of bitcoin in my country is relative with the USD equivalent of bitcoin. I think that in Africa the reason that it is popular is because it is more expensive to use their currency to buy necessities, and the equivalent of bitcoin in those countries are higher, if I am right, the price of bitcoin is relative to dollar in some African countries too.And most of people are afraid on USD because not unlike with Bitcoin, Bitcoin got only limited supply, which is 21 million.
Definitely those countries will not choose stablecoin over Bitcoin or other volatile cryptocurrencies since they are already aware of the decreasing purchasing power of their own fiat or with USD which is associated with the value of stablecoin. If the value of fiat currency will continue to decrease because of inflation then there will be no reason for them to go with the stablecoin which will also experience a decrease in value for the same reason as to what could possibly happen to fiat.
Moreover, through Bitcoin's volatility which can provide possible gains, these countries see that they can cope up with the inflation or decrease in the value of fiat and could possibly salvage them from the slumping economy.
