A lot of is about digital identity.
In a country where there is humananitarian crisis, I can't imagine recordkeeping and infrastructures are reliable enough to inform outside entities what is what.
Of course, IOG is going to be the consulting firm to help the governemnt utilizing Cardano. This is a private business deal between IOG and Ethiopia with a side of Cardano adoption.
In theory, nobody needs IOG's permission to use Cardano. But, it's helpful to have their insight and suggestions. How the government of Ethiopia use the tool after IOG is no longer needed is another story.
Idk, maybe @cardanoguru knows more than I do on this matter.
RE: Ethiopian government embraces blockchain technology