I don't have a great one but honestly I would use it to show / corroborate my side of the story. I.E. I didn't cut into a lane and get cut off. I wasn't too close to the guy in front. No I was in my lane and the guy turned into me. I don't need the plate or any super high details.
It was helpful the one time that my STI got hit by a pipe. Couldn't make out the truck or anything but it showed me driving along and BAM a loud noise.