I believe he is insured against loss in the event of an accident. So he doesn't need to drive around recording everyone just in case he has a crash.
I don't own a dash cam but there's scenarios where having a dash cam is very likely to assist with insurance claims. Whilst insurance is there for a reason, i.e. cover you in case something happens, I would prefer my insurance not to have to cover costs of an accident where I was not liable for said accident.
Some areas I can see why a dash cam would help:
- Hit and runs when your car is stationary (if dash cam has the feature to auto record when it senses a knock)
- Hit and runs when you're in the car and everything happens to quick that you can't catch the license plate
- Identification of driver if they claim they were not driving the car
I doubt people are pouring through their dash cam footage at every opportunity for privacy to be an issue, rather they review the footage if they're involved in an accident.
@OP I don't know too much about dash cams but just having more clear video will negate the need for ANPR features. I'm confident the same physics of cameras/camcorders would apply in a dash cam through, i.e. biggest sensor size possible, fast lens, fast read out to reduce rolling shutter and the ability to tweak compression levels.