I don't know if the government of any African country have adopted the system of paying salaries in Bitcoin, but I know here is Nigeria they haven't, it's possible to pay employees using Bitcoin or other crypto currencies ,
With the services of some crypto currency payroll agencies like Bitwage,papaya global, ontop, which will make it possible for the government to pay their workers in Bitcoin or other crypto currencies and can be sent into their digital wallet,
Since it has to do with the government another agency can be set up in the country in respect to paying salaries as Bitcoin which will somehow help in the growth of the economy of the country.
Think about it, is it useful for them to do that at the present time? Since most of the countries here have weak economies, it can be seen that they are not really ready to accept truly new things, in general, paper money is still a tool for them to use every day.
And if that proposal is applied, they will have to spend more budget to improve service quality. I find this idea not really convincing at the present time. Even countries with top economies are not ready to adopt that, although I can sense the potential of blockchain technology but let it take its natural course like how ETF comes as a inevitable with bitcoin.