You've missed a bit there, "allowing hard currency." Even if they don't allow it, bitcoin is still being adopted all around the world, that's the point. It can't be stopped and any country that bans or refuses to move towards a bitcoin standard is going to be left behind in poverty.
Try paying your soldiers when no one wants your money.
You’re assuming adoption happens equally at the same rate everywhere. What about if, as you say, the US government is unable to fund it’s military because it’s citizens and defence contractors only accept bitcoin, but lets say (hypothetically of course) Chinese or Russian citizens or contractors are more than happy to fight for payment in rubles or yuan, because let’s say, adoption has been slower in those countries? Not that this is actually based on, I don’t know, actual adoption rates between these countries or anything…
