Yes, we have reached the stage of a fiat money regime, one where the monetary medium is made of intrinsically worthless tokens of paper or some other inexpensive material.
Speech by Peter Praet, Member of the Executive Board of the ECB,
at the Bargeldsymposium organised by the Deutsche Bundesbank,
Frankfurt am Main, 10 October 2012
Yes, money basically is
– a medium of payment/exchange
– store of value
– unit of account
But since the 20th century, probably more so after 1971, it has become a commodity in itself. Things have become all so complicated. It is especially so, according to The Ecology of Money (Richard Douthwaite, 1999) when the different uses of money conflict against each other. For example, we may want a stable store of value for our monetary assets. But a strong and stable currency may reduce the exports of local goods overseas. The reduced revenue is a dear price for export focused economies.
Eventually, he advocates instituting up to five different types of currencies within a single state. Some side effects (or as economists call them externalities) would be a greener and more stable economy. The concept is new to me and, unfortunately, I am unable to digest it well. Perhaps, you could give it a try. There is a revised 2006 version.