I use both e ink and tablet for reading, but have started to use the e ink devices more lately. I can certainly see the differences in how people use both and why.
Story : I became a grandmother for the first time in December, my daughter and I took the baby out in a stroller when we had the first nice warm 60's day, a couple weeks ago. We walked in her neighborhood and I saw for the first time a free library box ( looks like a very colorful mail box.) I asked " Whats that ? " She told me ,it has free books inside that people in the neighborhood donate for others to read." So we went over, and she asked if I wanted a book ? I said no I use an e reader now. She asked , but don't you read paper books too ? I said only sometimes, but not very often anymore. She said oh yeah you gave me a Kindle right ? I replied yes, don't you use it ? She said only at the beach. The rest of the time I read on my phone.
So I can certainly understand that people read on different devices for different reasons. She did take a paper book from the book box though. She said sometimes she just likes holding a book too.