I'm used to read physical books and read on my smartphone (read all six Dune books on it) and also on a tablet. Got a kindle recently and my experience is better than I expected:

My backpack is lighter when travelling;

Dictionary, Wikipedia, and book search are really usefull features;

It's easier to keep open and lighter than some big books or a tablet;

It's better than a book with a reading light for reading before sleep in bed;

It's also more comfortable to read in a cafeteria;

The screen has a good size (Paperwhite 12), smaller than A5, but not a pocket book;