The currency of international trade has been on a lot of peoples' minds in the last few years. The hierarchy of currencies literature, the related questions of reforming the international monetary and financial system (IMFS), the effects of US monetary policy on the rest of the world (ROW). Add to that the war in Ukraine and Chinese trade-related discussion on the role of the ruble, dollar, yuan, oil and natural gas, wheat etc.
Hierarchy of Currencies
In modern states, demand for currency comes from the ongoing self-imposed liability for the currency. There is no need to pay savers in order for them to desire to hold the currency (interest on sovereign bonds issued for "deficit spending"). Any justification for doing so must rest on some other perceived benefit of paying savers.