I don't say that at all. Money spent on BS still sucks resources, no matter who spends that money. They are not going to make the GPU's from 500 billion dollar banknotes, they will pay people $500B to work on this stuff which means people won't be working on other stuff that can actually produce value worth more than the $500B.
By that logic all money is waste. The money isnt destroyed when it is spent. It is transferred into someone else's bank account only. This process repeats recursively until taxation returns all money back to the treasury to be spent again. And out of this process of money shuffling: entire nations full of power plants!
Money is just IOUs, it means for some reason not specified on the banknote you are owed services. If in a society a small group of people are owed all the services they can indeed commission all those people.
If your rich spend all their money on building pyramids you end up with pyramids instead of something else. They could have chosen to make irrigation systems and have a productive output that makes the whole society more prosperous. Either way the workers get their money, on the Pyramid option their money ends up buying much less food though.
I guess the power plants are salvageable.