I do think they are a good idea but it adds one more chore to do before setting off. I will then have a TomTom, DashCam and my rear view monitor to watch in addition to the speed, fuel gauge, fuel consumption, engine temperature and my mirrors. I am still expected to glance from time to time through the windscreen; to admire the view.
"Sorry dear, what was that you were telling me?"
Meanwhile my feet are pushing throttle, brake and clutch when I am not deciding to switch off or on the cruise control.
Yes! I think the dash cam may well be a useful aid, to spot if and when I go wrong.