I agree that USD, regardless of its waining value, is fairly universal. If I was going to start a country, I would start with USD as the currency instead of risking insane volatility. However, as discussed in the Bitcoin whitepaper, one of its pinnacle features is it is (supposedly) not controlled by a single entity or government or private institution, or really any institution. So the advantage of USD being tethered to the USA government is both a feature and a flaw, and BTC not being tethered to anything is both a feature and a flaw.