Q: When a currency is devalued by hyper-inflation from printing too much money who benefits? A: The person printing the money.

Governments that devalue their currencies by printing way too much have no incentive to switch to another currency. Printing money is an indirect tax on the current holders of money.

The only way a country like Zimbabwe would switch to Bitcoin is if the people revolted and forced them to. African nations have rampant corruption so while it might be one of the best things that could happen economically it is very unlikely politically.