Don't (really) get me started on dust jackets and covers on paper books.
<rant>
Books you can't tell the difference between, because:
They all use the same color scheme and little else different besides the words in the title on the spine. Not all books are shelved FACE OUT
Note that ACE used the Yellow and Red/Black scheme BUT they frequently varied the FONT
The Author Name is most prominent on the spine. Gee, I am in the 'J' section, I think I can find the 'Jones' books
The top (1/3) portion taken up with only Logos/Author name/Series. Anything but the Title. This really works well
when displaying books (face out) on a tiered (overlap) rack display
</rant>
Covers DO sell Books
Spines allow books to be selected from your shelves (Yea! IKEA Billy
)
Cover images do allow for the same kind of E-book selection that is not just limited to the initial Sales event.