I mean, reflected light is less harmful. We aren’t looking directly at the sun for it leaves ghost shapes even after we turn our head, but it’s lights’ reflections is what makes or eyes see. Basic e-Inks don’t emit light, some backlit it from the side, or from the back, but they are still more safe than displays that do work by emmiting light of some color directly to you, and there was a race to reach the wider angle they can do it too, for older devices had colors nearly inverted if seen from the sharp angle.