^They weren't a government entity. That may very will be a huge difference, legally.
Right but the federal government has the right to regulate currency not the states ... that was one of problems of the articles of confederation - why they had to re-do it and came up with the constitution ... in the constitution it gives the federal government that right and illegalizes the state currency ... kinda weird that they wanna do this now ... this was already sorted out pre-1800's ...
I could be wrong, because I really didn't pay that much attention to the issue, but I seem to recall your argument being correct for interstate use of currency, but not for currency used solely within the borders of the individual states.
SC has also tried this for incandescent bulbs and, most recently, guns