Earlier quoted context omitted.
The USA actually does have laws against creating anything that might be interpreted as competing with the official currency. This is the most likely avenue for violence to come in, as people try to resist devalued money by using substitutes.
There are generally no laws in the USA against creating and using alternative currencies. I can buy and sell using Euros or Monopoly money or whatever if I can find a willing counterparty. However, if those transactions are taxable then I have to report them at the US Dollar fair market value equivalent and pay any taxes due in US Dollars. And if someone owes me a debt I am required to accept US Dollars for settlemen…
This is not correct. If you try minting coins, you can be shut down. You can buy and sell using whatever you want, yes. There aren't laws against using alternative currencies. But there very much are laws against creating them.