Reading standard screens is impossible in full daylight and also leads to sore eyes.
That may have been true five years ago, but it isn't really true today. It's been a really long time since I've had to cover my phone to read something on it, or needed to go inside. Screens have definitely gotten better in the "reading in the daylight" category. But E-Ink hasn't gotten much better in the "reading in the dark" category.