Just like the headline says. I mean the vignette that you can remove when you press Pause, not all the fatigue effects etc. It's not practical that we need to press that key everytime when playing or starting a new mission (maybe even respawn resets thins I'm not sure).
It's just an ugly effect that doesn't give anything to the game for me.
I guess many don't even know that we have a key for this but I remember this since alpha/beta :P