https://www.treasury.gov/resource-center/faqs/Currency/Pages...
> Federal Reserve notes are not redeemable in gold, silver or any other commodity, and receive no backing by anything
There are no limits to currencies. No limits to how much money governments will print. No limits to how much the banks will inflate the money supply through loans.
Disclaimer: A significant part of my investment portfolio is in Defi.
So it is not really about reputation or violence being used against those who would "interfere" with the dollar (whatever that means). I would argue that the value of the Yen is more influenced by reputation than that of the dollar, since people tend to treat Yen as a "safe haven" during economic crises (but ultimately the Yen's value primarily follows from the Japanese government's ability to enforce its laws).
Also by the fact that the companies of the S&P 500, who are generally based in the US, account for a large portion of global transactions, which they tend to do with USD. If anyone wants to participate in the global economy, the USD often provides the least amount of friction in transactions.
The other most popular/useful/"valuable" currencies, per forex trading volume, are: EUR, JPY, GBP, AUD, CHF, CAD.
* https://en.wikipedia.org/wiki/Foreign_exchange_market#Tradin...
This puts a hard limit on the number of currencies, and how much they'll dillute the dollar (or any other country's currency). Since you'll normally only see a single currency per government.
Cryptocurrencies on the other hand, aren't tied to any country.
There's no hard limit on the amount of them. So every time a new one shows up, they'll they'll take a piece of the cake from the already existing ones, since the space is limited by the number of people willing to invest in them and how much these people have to invest.