One of the core improvements over traditional books, is portability.
I can carry around 100s of books whenever I travel - without having suitcases packed with them.
To compare this with ebooks is pretty strange, considering the portability is 0. It's basically saying "you can have multiple books open at the same time which keep their reading position".
Great, you have multiple tabs in a browser open now - you've achieved it.
Being the happy owner of an ebook reader I just can't force myself to pick up a dead-tree book. Even though I have a dozen waiting for me to start them. It won't happen.
E-ink + Configurable font + Touch screen = Reading bliss
I read a lot, and was reluctant to getting a kindle. Now I've owned one for a year and I wouldn't go back. Being able to read from bed without glasses, with a bit of light from the device itself is just perfect to me for reading at night.
It's much more portable - which is great! The battery life is also amazing on those devices so my worry of having to charge them too often quickly disappeared.
The only books I do (sometimes) read in 'dead-tree books' are the more technical ones. But even those I'm starting to replace - some programming books have images embedded where the fragments of code are, so the formatting is preserved as the kindle can show the images perfectly fine.
The convenience and comfort of a kindle is just amazing - but for some more technical books with bad ebook support you still need traditional books.
I do tend to buy traditional books from time to time though - becaus I like the way they look on my bookshelves. Though now only for books I really like and want to be reminded about when I'm looking around in my room ^^
It's a ferris wheel of books for the purpose of referencing multiple books when you're too tormented with gout to walk around a table.