It does actually because they didn't pay people who will spend it with that money, as in workers. Is just rich people exchanging it.

All this money kept out of circulation leads to an increase in purchasing power of all the other money in the world. A bit like when the KLF burned a million quid.

Give me 90% of your $100, it'll increase your 10 dollar's buying power

Suppose there are two possibilities. The transaction could occur, or it could not occur. If the transaction occurs, how does the world 'actually' become poorer as you assert? What's the mechanism that takes value from other people, or otherwise harms them, when this transaction occurs?

It's about the other options for the money other then art. If they had hired people to work, the world would be richer.

They can still hire people and pay them. The situation is the same as before the translation it's just another person with 100m now and a different one with a painting. There is no waste there.

But the money didn't disappear either. Now the person that got the money can do that. If the money is kept from circulation for a long time that's obviously good for everyone else as more their purchasing power for things like homes and food increases.

An exchange of processed resources, which is where the wastage goes.