There are serious problems with money, and if you don't know the main one, try doing without it for a while.
Money makes the world go round - but only when it does.
It's just as true to say when money isn't moving, it stops the world. Things don't happen until money gives its permission. No money, no go. These problems exist because of a simple misconception deeply embedded in the way money is taken to exist - indeed from the very idea that it does in fact exist, that it is some sort of real thing. The money we commonly use was never designed.