For me, it was a space-saving measure. No more room for bookshelves or books, except every once in awhile when I cull through (In terms of numbers, I try to buy only what I get rid of so as to keep the numbers the same). I've found my ereader much easier for travelling, taking to work to read on breaks, etc. But I just can't buy books the way I used to...otherwise it'll get to be like something on Hoarders, lol. Still enjoy browsing and looking at paper books.
I'm also a bit of a gadget geek, so I enjoy the gadget aspect too.