In some real economic sense the money is gone, though. Think for a moment of money not as some abstract numbers, but a representation of a claim on actual, real

In some real economic sense the money is gone, though. Think for a moment of money not as some abstract numbers, but a representation of a claim on actual, real resources and suppose for example you go for a haircut, stop at a cafe on the way back, have a coffee and a pastry, all in the local economy. The resources you've consumed - the coffee and food, the workers' time, the space in the cafe and barbers - all those are gone, they don't recirculate. When that money gets spent, the person spending it is claiming a whole new set of resources with (in a sense) new money created through the process of it circulating within the economy. One interesting corollary of this is that speeding up the recirculation of money increases the money supply and slowing it down decreases it, just as though some central bank was actually printing or destroying money. This is particularly relevant right now, when a lot of countries seem to be running the metaphorical money printers flat out and the circulation of money has been temporarily impaired by extremely limited things to spend it on.