The fact that dollars are widely used in international markets, e.g. in oil trading, is what enables the US to borrow money abroad in its own currency. Which is

The fact that dollars are widely used in international markets, e.g. in oil trading, is what enables the US to borrow money abroad in its own currency. Which is a pretty big deal, since owing money in currency you don't control (which of course is what most nations have to do) leaves you vulnerable if there is a downturn in your economy and your currency weakens. Keeping the status of the dollar as a major reserve and trade currency is important to the USA.