Me too. And as you get older, with more books behind you, a dust jacket is invaluable as a reminder of what the hell the book was about.
I use the flaps as bookmarks too.
Ditto on the artwork. Several years ago I fell in love with the cover art on Laura Kalpakian’s Graced Land. I wrote a complimentary letter to the publisher and they sent me several postcards of the cover, and a larger version that I framed. Is that cool or what!?!
I’ll pay extra for a book with DJ, and I try to keep mine in good shape. Not for resale, but just because I like DJs.