Even if no painting is involved, take Fontana's "Tagli" (cuts), at least you have something in your hands.

I mean, as a museum curator, after investing some money, I have something to attract guests and sell tickets. Imagine going to an exhibition to admire an invisible artwork, that requires a whole new level of faith.

I rest convinced that buying nothing, even if this nothing is backed by a certificate of authenticity, is a stupid thing to do. But since auction houses are everything but stupid I feel that's something else going on, and no, it's not abstract art.