[tpool]

I think they buy these kinds of things for less philanthropic reasons and more for the same reason that the ultra wealthy invest in art: an asset that never loses and often increases in value. It’s a haven for their wealth. If you can “loan” it to professionals (e.g. a museum) who will take care of it for free, and the public can enjoy it too? It’s a solid PR move as well.

[tetris11]

It's also wealth that can be transferred seemingly without any import/export restrictions by an Art Dealer. Because, it's art, of course.