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.
OP, have you ever thought of this, if the government for example decides to pay salaries with bitcoin don't you think their will extra charges, the transaction fee is high and the fee that will be used in facilitating the payment can be channeled into other stuff, if African countries government eventually do this which I know that is wont be possible, it wouldn't change anything, what African need is eradication of poverty in the land not payment of salary with Bitcoin, poverty has dealt with Africa to the extent that the leaders should be considering a means of bringing their people people out of it with the resource available.