Large format artwork, limited edition/numbered pressings for collectability, limited edition/numbered pressings to try and sell on for a personal profit, supporting the band by purchasing a physical piece of merchandise perhaps directly from them, being part of a trend they've seen on TikTok/Instagram, etc.

Many reasons. A lot of the same reasons people buy, say, Pokemon cards and don't play the card game.

As objets d'art. The thinking is that owning (and crucially, displaying) vinyl records marks you out as being more discerning than the rest of the herd.