Hardback books seem like a magnet for collectors (hoarders) they know they could more conveniently get the book as an ebook or from the library but they are buying them primarily as an item to store on a shelf. I have seen people buy books they don't even intend to read simply because the hardback is well decorated and the edge of the pages is gold.

Perhaps they think the sight of a large bookshelf full of books they never read makes them look smarter. They are probably right as well.