Is E Ink anything more than a marketed technology with no real purpose?
One can calibrate the brightness, white balance (e.g. Apple's True Tone), resolution, etc of a regular LCD or OLED display so that the same amount of photons hit your eye (and are more tightly controlled when you move the display around) as with an E Ink display, and get better resolution color, and saturation to boot.
Besides the idea that it was easier on the eyes was never backed by any substantial scientific studies, it was just "but it's like paper, so it should be" plus some manufacturer sponsored crap.
Well, there's the extended battery life I guess...
Screen persistance with zero power can be a pretty big deal. It's always nice (ish) when my Kindle has the 'your battery is dead' screen on when I go to use it, so I know what's going on even before I try to turn it on.
Other than that, it's hard to compare because nobody makes large monochrome lcd displays. Monochrome is actually a feature for the intended use: newspapers and books use a pretty limited amount of color, so you get improved pixel density and geometry without having to split pixels into colors.
OLED won't work for dark text on a light background, and tends to be rather expensive -- I can't imagine a Kindle sized device with an oled display for less than $200, so that limits it to the high end models.
I have a Kindle reader with an E Ink display. It is much more pleasant to look at in daylight, especially when ambient light is very bright.
Battery life is also much, much better. My tablet lasts two to three days at most, under light load, with power saving turned up to eleven. The Kindle can easily last one to two weeks. (It all depends on usage patterns, of course, but for my case those are the numbers I come up with.)
I do agree, though, that it is hard for me to think of a use case other than an ebook reader. For that particular case it is perfect, though.
One can calibrate the brightness, white balance (e.g. Apple's True Tone), resolution, etc of a regular LCD or OLED display so that the same amount of photons hit your eye (and are more tightly controlled when you move the display around) as with an E Ink display, and get better resolution color, and saturation to boot.
Besides the idea that it was easier on the eyes was never backed by any substantial scientific studies, it was just "but it's like paper, so it should be" plus some manufacturer sponsored crap.
Well, there's the extended battery life I guess...