The yuan may be the competition we should fear. Since we disconnected Russia from our financial systems, Russia is willing to do business with our biggest rival, China, in their currency.
[1] https://finance.yahoo.com/news/putin-strengthening-yuan-role...
Money flees China now despite the capital controls.
Even the Chinese would rather keep their money in Singapore, Switzerland or the US than at home.
When Korea buys something from Japan, they don’t have to pay in USD. They can use whatever currency they want.