more appropriately...why WOULDN’T they want to do that? the Federal government has been taken over by those who absolutely HATE the Freedoms afforded by our Constitution and Bill of Rights as written so for literally DECADES they have lied, cheated, stolen, abrogated and obfuscated the truth that Our Founding Fathers tried to impart to us that would ultimately protect the typical American citizen from financial ruin. “What you do now lays the foundation for what happens to you next” is as true now as it ever was. saying by L.Star.
They'd have to buy gold and or silver. Store it. Print money. Set up a conversion rate. Set up offices to exchange gold/silver for the state currency. Set up a separate tax collection database, to collect taxes in US dollars and their own currency.
Probably a bunch of other things as well.
What did they gain with all that extra effort and expense?