When buying my tiny ereader, here were my reasons to why it was a good idea:
1. I can't bring piles of books home in my suitcase, because there is just no room!
2. I want novels for reading and hauling around on trips and things, but they are heavy and again, take up a lot of room.
3. Lots of research is on pdf's which I hate reading on the computer (screen hurts your eyes after a while), and printing takes up sooo much ink. Put it on the kobo thing, problem solved!
4. I have an illustration in a published article, and I wanted to see it on the ink paper.