Yes there is. Typically money is legal tender, which means you’re mandated to accept it by a government with large numbers of guns and prison cells.
That’s what for all debts public and private means.
> Yes there is. Typically money is legal tender ...
Parent comment was right, subjective value thesis says people will value things (including money) differently.
And legal tender laws are only "typical" of government coercion in the central bank era, basically the past century or so. Prior to that the king or the local sovereign may have required taxes paid in his coin, but multiple monies circulated and people freely chose which ones to spend, save, accept, or not.
And were routinely scammed out of their savings as a result, it should be noted.
For a global economy, we need a global currency, and USD/EUR have been the closest thing to that so far.
So is crypto. Some people came up with a collective hallucination that they considered useful and valuable, and convinced some other people that it was, because, hey, we all like valuable things, especially when we can create them out of thin air and sell them to people for other shiny things that we like.