Lots of people. This is great for office workers, because e-ink doesn't cause eye strain like monitors do. And if all you're doing is working with documents, this is a fantastic way to go.
If it were more reasonably priced, I'd be excited to buy one. I sit in front of a screenful of code all day and it's tiring on the eyes. Black-and-white e-ink is not as desirable because it's helpful to have colourful syntax highlighting.