> It's as much a gun to adversaries' heads if they hold lots of your bonds (China used to hold over $1T in USTs)

There is a complicated dynamic at play to consider there. Treasuries and the strength of the dollar only matter to wrt international trade, for both China and the US. You have to ask yourself if the value of the dollar went to 0 for that use case, who would be in a worse position, the one that sells dollars to support consumption, or the one that buys them as a tool for trade with 3rd parties?