This is one thing I've heard repeated - that USD needs to be spent in America - seems like other countries could just transact with it directly.
It's worth observing that dollars that are never supposed to return to the US don't have the same anti-counterfeiting pressure that dollars spent in the US do. I don't know how much of a market there is in counterfeiting USD for dollarized economies.
Not to mention, that would break fungibility.
Can you provide a source?
A source... for what claim? What do you think I'm saying?