I've used one of these devices in my car for the last couple of years and have enjoyed really cheap car insurance as a result (variable based on my driving but usually $30-$35 CAD/month).

It is very true that if you are driving in rush hour traffic you have no choice but to appear to be a bad driver. The irony of this is that the accident happening in rush hour is probably minor, yet when I'm barrelling down the highway at a steady pace I appear to be a great driver whereas an accident would be very costly (fatal perhaps).

Also they normalize your infractions (sharp breaking, sharp acceleration, speeding, etc) by distance driven so long highway driving is even more beneficial (few infractions, long distances) than traffic jams (many infractions, short distances).