if they will use usd as a medium for paying on imported stocks then what do you think will be the purpose of thier own local currency ? only for display ? no no no , they dont hodl and use usd for buying goods abroad but they can still be able to pay using thier local currency or they can just use thier cc and other payment methods which automatically convert thier currency into usd and other international curreny but they can be able to save up if they will use cryptos . its possible , i heard many governments already adopt crypto and as well as blockchain technology . others are still pending and awaiting for approval