For me e-ink is a superior way to read because I can't handle reading pages and pages of text on my tablet. I use my Nexus 7 exclusively for Web surfing and videos but in have tried using it to read novels and have failed I just can't get used to it. My e-ink Kindle is the only way to go. Even with a reading light attached I have no problems reading on it for extended periods of time.
So I think a tablet and an e-reader can coexist.