International payments need a common standard to avoid messy exchange rates and hence the UK pound was the global currency until after WW2. Due to the national debt level the US$ became the new currency to be used globally.
As crypto emerges & is being used for many transactions, BTC seems set to hold a place for large transactions, and or international ones such as a Japanese money transfer company creating contracts for BTC payment with Africa.
Crypto is starting to go mainstream.
Time will tell