If you didn’t know, there’s an active market for collectible sneakers. You’ll periodically hear that someone like say Dahntay Jones has a vast collection (in his case had, unfortunately).
So to an extent that may explain why someone was willing to pay $19,000 for a used pair of Zion Williamson’s - Kyrie 5’s if you’re curious.
Almost every investment is speculative but even with that said, it’s hard to imagine spending that kind of money on someone else’s shoes.