I am not sure if either of the two effects you listed are behind this. I think the most notable issues include:

1. Less brightness as measured in nits. Emmissive displays are often tuned to much higher brightness than normal objects around us including reflective displays like E-ink.

2. Reflective displays and paper often have significantly lower front-surface reflection than LCDs/OLED displays. Add touch-screen and it gets ruined beyond repairs.

The first one is easy to tune by reducing brightness levels. However (A) that makes the second one worse as the brightness of the displayed content reduces but the brightness of reflection does not, and (B) displays are often too bright even at their lowest brightness levels allowed. Put a white paper in the front of white background on the screen, and you'll see what I mean.