This is the story of how someone else’s cover art can sell your book.
Cover art is powerful.
*That* image, which you recognize as a thumbnail, or even as a corner of a tattered paperback sticking out of a pile of stuff, conveys so much more than just a sketch of the main character.
It continues to sell the book even after the book has been sold once, twice, thrice and is making the rounds at the library book sales.
It gives the author an image. Consistent cover art with similar design motifs from one volume to the next tie all of the author’s books together as a uniform package.
It also invites conversation.
The lack of cover art is the single thing I dislike the most about e-format. Not that the books aren’t displayed on the virtual bookshelves with a thumbnail image– I know that’s there. I hate that the e-device itself doesn’t display the cover to a passer-by.
Last Friday I walked into the pottery studio and this was on the worktable next to another potter’s workspace. It was face down, open on the table, and I could see that she was about 2/3 of the way through the book. I could see that she borrowed it or bought it used. I could see that she was likely to enjoy many of the same books I do. All this before I even knew her name.
Because that book was there, displaying its cover, we talked for a long time about our faves. That book and its cover made many more book sales beyond its own title, author and publisher.
Alternatively, another lady was reading a kindle and eating by herself at a table next to where we were playing Munchkin this weekend. I have no idea what she was reading. No cover, no discussion, no new book sales, no new friendships made. A table of five SF/F avid readers and participants in NaNoWriMo had no reason to interrupt her lunch.
Here’s what Margaret the Potter Gal and I discussed:
Garth Nix, Sabriel series plus other series not Sabriel.
Alan Dean Foster, Pip and Flinx, plus the one about the dog
So You Want to Be a Wizard, Diane Duane
Wandering Star graphic novel, Terri S. Wood
Who Fears Death, Nnedi Okorafor
Leviathan Wakes, James S. A. Corey
Thraxas series by Martin Scott 
Sookie Stackhouse series by Charlaine Harris
Tanya Huff’s Valor series and Blood Price series
Because Kristen Britain’s Green Rider was face down open on a table, I went out and purchased Alan Dean Foster’s The Light Years Beneath My Feet and Clive Barker’s Abarat. This conversation and these purchases likely never would have happened if Margaret were reading on an e-book device.
If publishers let cover art die, they’re killing the industry.

Oh yeah! Also Barb and J. C. Hendee’s Noble Dead series.
Cover art is hugely important. I am waiting for the eReader device that as an LED display on the back that shows what book is open on the reader. eReader manufacturers should redesign their systems so they switch to “screen savers” after a few idle minutes, and the screen saver should be the cover image.
In the mean time, we should be able to create custom eReader covers that are the “cover” of our favorite book.
Wait, I have to go put this idea into our eBook “apps” idea queue…
When I read my e-reader in public, they ask how I like the e-reader; they don’t ask what am I reading and how do I like the book.
Jacqueline Carey’s Terre D’Ange series has great cover art all the way through.
On some level I hear what you’re saying, but to be honest, while I was in Italy last week, I finished a ridiculous number of books. I was quite shocked. And if I hadn’t had my Kindle, I can guarantee I wouldn’t have had those books with me. Let’s see, I finished Les Miserables by Hugo, An Evening of Long Goodbyes by Paul Murray, The Stepford Wives by Ira Levin, Dragon Haven by Robin Hobb, Book of Secrets by Chris Roberson, and The Mall by S.L. Grey. I don’t think I would have been able to bring six books with me (especially Les Mis, it’s 1000+ pages, of which I was about 3/4 of the way through when I started on the trip). I even started on a seventh as well. But you’re right, it’s not like someone would ask me what I’m reading on my Kindle.