...and I'd do it in a minute if I lived in one of the big traffic hells like DC, ATL, L.A., or DFW. Besides, without a camera on board, how will you get lucky video of a meteor exploding overhead?
Having had someone try to by-god kill me while I was just riding along and minding my own business before, I can see the value in a dash cam. Check out the footage Rational Gun got within two weeks of installing one; if he'd actually hit that dude, the camera would have paid for itself many times over in an instant.
(Fortunately, in my case, the dude was a mensch and pleaded guilty in court. Things could have dragged out longer than they did if he hadn't owned up to his screwup. That's not the kind of thing you can count on, sadly.)