This contrast on paper is quite high and typical displays feature a low contrast. Finding a display with a high contrast coating will make it easier for you to read what is being displayed. The result of the easier reading is increased productivity.
Contrast ratio is the difference in light levels of the white backgrounds and the black text.
White is created by both the light being emitted from the glowing phosphors and the light reflecting off the screen. Black characters are only the result of light reflecting off the screen, not light being emitted from the display. In a dark room you would have a high contrast ratio, because the whites would be at a high level of light, and the black would be very low, because there is no reflected light. Reflective light offers the same intensity whether it reflects off black or white. In the absence of reflection, you will have a high contrast ratio.