>As far as I know, in the U.S. you are free to print your own paper currency
This is not the case, when a 'private' currency gains traction or seemingly encroaches a territory, which is traditionally assigned to government ─ it gets shutdown.
https://www.nytimes.com/2012/10/25/us/liberty-dollar-creator...
https://www.openpr.com/news/25136/TUC-IMPROVING-THE-US-ECONO...