Don't most red dots still have iron sites visible even if the dot is damaged. Im sure it still is in the way, and site view isn't as good. I personally have never shot a pistol with red dot, so I'm talking out of my butt based on pictures, videos, ect. I have considered getting one, because I'm a terrible pistol shoot, but haven't made the move yet.
Speaking of pistols, if you've never watched "Buffalo Outdoors" 'A man has to know his limits' its insane what he can do at 80-110 yards with pistols, and no special sites.