> And it would be impossible to bail out those bonds when they defaulted

Well the US hasn't defaulted so changing how a default works wouldn't really affect the trajectory we took. And a default would be pretty catastrophic either way.

> nor to reuse the bonds to back money.

I don't know what you mean here.

Well the US isn't on the gold standard. If it was on the gold standard then it would have defaulted. That's why it moved off the gold standard.

Actually, by moving off the gold standard, it defaulted on dollars (at the time a kind of gold bond) rather than defaulting on dollar-denominated government bonds.