You are correct. All the other currencies used to be pegged to USD during the time the gold standard was still a thing. But Nixon changed this and you can no longer redeem gold for USD. But all the other countries just left their currencies pegged to USD because during the mid 20th century USA had more gold than rest of the world combined and their economic dominance was unchallenged.
When it comes to fiat currency, USA has the least to worry about.