During the beta for Call of Duty: Modern Warfare, one of the feedback points surrounding the game was the screen going black/white when you were injured in game, which in many cases took away the immersion from the overall game.
Infinity Ward has explained that this was intentional design decision as part of the overall flow of the game.
Infinity Ward’s Art Director said on Reddit that it’s especially useful when using it with the Stim equipment as players can tell when their health is generating back up and ready to move.
Watch someone who is really good with stim and notice how important the shift from the desaturated vision to color vision is. It informs game play. Tells you how close you are to death.
He also explained that even without stim, it’s a way to know when you can push back out in action in game.
Not just stims. If you survive an encounter it indicates when it’s safe to push or bound out.
Infinity Ward’s Senior CM also mentioned on Twitter during the beta that it is in game for a reason. It allows players to have a clear understanding of when they’re weak in game.
This is a new decision for Call of Duty, as previous games have the screen just turn red with blood splatter on it to indicate when the player is injured.