I bought so many unread books on my kindle that I'm now back on shoulder breaking (i.e. heavy), paper books for the following reasons:
- The size volume and weight of a book allow an automated limitation system.
- I can clearly see how many do I have
- I can carry only one at a time and put other stuff to read on a list of to-buy
- I feel I have to read my book before removing it from my bag
- I can easily give to charity the book that do not deserve to stay in my limited book space