True, but it isn't scarce. It's printable by a certain few who use it enrich themselves and oppress others. In some countries, we have monetary systems that still work, more or less, but built on deception and oppression. Our pension funds are laughable Ponzi schemes, but legal because they're government-operated. At least the private ones are voluntary! In some countries, they don't have a working fiat system - many citizens don't have access to banking, and currencies are so useless they use foreign ones instead. It's "working" in the sense you suggest - if it's a tool intended to increase government control, drain the wealth of the people, etc., then it's doing its job quite well.