Google “detroit dollars”
They can , do , and have...
It isn’t “real.”
It is like having a club using Monopoly Money where everyone agrees that they will accept coupons at some face value.
The moment you try to use the coupons outside the club (to pay, for example, an auto loan or worse, to pay taxes) you violate the federal Guidelines.
Yeah, you can have a club if you want, but you can’t force the citizenry to participate. That also crosses the line.