I fully agree that anything can be "currency". Grocery coupons satisfy the standard requirement to be considered currency. The problem is getting them widely accepted so they can scale up to meet the extreme demand needed for a country as large and resource-rich as America.

Such scaling requires universal demand, and that can only be created by a universal tax levied by an entity that can enforce it. Once such a tax is levied that entity (the federal government in the US) then must make sure that it supplies sufficient currency into the economy to satisfy the tax as well as the population's desire to net save.

Such a currency-issuing government never "needs" its own currency back after it it spent into the private sector except to control inflation by limiting reserves in the system or controling inequity. It does, however, need "us" to need its currency, which is the primary purpose of taxation.

It also has to be cautious that it doesn't overtax the population, leaving no "deficit" spending to compensate the private sector for the resources and labor it consumes at a fair price. Such is the stuff revolutions are made from when the people figure out their government is stealing from them. Every dollar in deficit spent by the currency-issuing government becomes someone's asset in the private sector that is able to retire private bank debt and be net saved.

If our idiot representatives understood their own jobs and how their government funds the economy the people would be unlikely to have any desire to have conversations such as we are now having.