I think both of you have a point and there is a value in minimalism, but for me I enjoy the combination of having really portable way to read books without distraction and at the same time having a feeling that I have a nice library of books that I own, I can always look at and I can always check remember the books I read and check through books to read next.

If you set the phone for Night Light (to disable blue light), reduce the brightness to minimum, and set white text on black background, then it's fairly easy to read in full dark (on OLED displays).