The camera would not have stopped the loss of life - nor would a DFDR or CVR. What a camera does is make it IMMEDIATELY apparent that the FO was actually alive and well and sitting in his seat and stop all this continuous hamster wheel in the media and here about different ways he could have passed out and still locked the captain out. In many previous events SME's have sat for hours trying to work out what noises were.
Camera is easily defeated with a piece of tape over the lens. Though even that would have indicated intent.