yea, I'm torn
for physicals - I've restricted my purchases to what I'm going to have as part of my 'permanent' collection, and there's only so much space (and $$) I have one collection of books in my living room, most leather bound (or have the look of leather bound) a lot of classic sci fi/fantasy, some limited editions, signed by author etc. A second collection is in my office (and is about to get purged) hardcover book club editions, mass market paperbacks etc. I have about 2x what I want to keep. (and that will give me space to add more LN physicals of which I only have a few)
That being said - I like the cover art to invoke the 'spirit' of the story dark/somber or light/humorous - I especially like when a series has cover art that themselves have a theme over the series of volumes (introductions of characters, or featured character on each volume doing something that relates to previous/next-- like the art has its own arc)- Shomin Sample, does this well as does Rokojouma. I'm not such a purist that cover art...needs to be on the cover, I'd buy leather(ette) bound Bookworm editions that had minimalist cover/spine art (like just Rozemynes crest) as long as all the art was inside