I meant "liability" in the sense of "is the US's status as the global reserve currency, on balance, a bad thing for the US?" not in the sense of "Is a US dollar abroad an asset or a liability on America's balance sheet?" Probably could have used a better word.
Sure it's not exactly an IOU but it more or less entitles you to a certain bit of the American people's labor or assets. Billions / Trillions of dollars in USD overseas waiting to be traded in is not a good thing for people who aren't in a position of international rent seeking. The average American is harmed not helped by foreign trade.
