Books are fairly portable, when you carry them one at a time. I can see the point of an e-reader for multiple copies however. Years ago being pocket sized was a regularly advertised virtue and the scores of Everyman and little hardback Oxford World Classics, like this one, that pass through my hands each year are testament to their continued popularity. I do still get the odd book search requests for "any edition so long as it will go in a pocket" usually from older gentlemen, younger ones I guess are all kindled-up.
Anyway, are pocket books fighting back? Hodder and Stoughton have flipped the text through 90 degrees and with thin pages and hardback covers come up with these little portable flip books. What do you think?