The point of the article is that around the world very large amounts of loans have been denominated in US dollars, even in countries that don't use USD. That means there is always a constant and large demand for USD to repay those loans.

So outside of the US, no USD is not just a store of savings, it's a means of repaying debt. Hence why people want it and will accept it as a first preference over most other currencies when international transactions need to be made.