Problem with money is that money only have value when people are willing to exchange money for goods and services.

The moment that exchange stops, value of money plummets.

A very good analogy I saw in Charles Stross’ “Neptune’s brood” is that money is a concrete representation of an abstract debt. Exchange materializes that debt into a trade, which is where valuation happens. I’m pretty sure I just made a lot of economists justifiably angry though