Clarifying my first point: it's often possible to select amongst a range of quality/refresh options for a given display, either globally or for a given app (as with an Android e-ink tablet).
In which case, higher display quality (more pixels, sharper boundaries, deeper blacks, whiter whites, and less ghosting) tends to come with slower display response.
When you're reading static text, page-by-page, that's an acceptable trade-off. If you want to scroll, zoom, or pan through content, or are looking at animations or video, you'll want lower definition & sharpness but higher refresh.
And remember that once an image is displayed, it will persist indefinitely without further power to the display.
In which case, higher display quality (more pixels, sharper boundaries, deeper blacks, whiter whites, and less ghosting) tends to come with slower display response.
When you're reading static text, page-by-page, that's an acceptable trade-off. If you want to scroll, zoom, or pan through content, or are looking at animations or video, you'll want lower definition & sharpness but higher refresh.
And remember that once an image is displayed, it will persist indefinitely without further power to the display.