Although many of us still like the experience of reading paper books, the convenience of having a ton of digital books at your fingertips is undeniable.
Whether you have a Nook or Kindle (or a competing) device, or use one of their apps on your other devices, the convenience factor is phenomenal.
Of course, having your books with you all the time also makes it likely that you will read more, such as when in line at Starbucks or the bank, or waiting for an appointment, etc...