Another point for an internal
Another point for an internal camera is face/eye tracking. I worked on a project many years ago for Toyota/Lexus that used IR cameras to identify and track bicyclists and pedestrians at night for accident avoidance. But they also had an internal camera for what they called inattentive driver. It tracked your face and eyes to first make sure that you were awake, and then that you were watching the road. It had a series of flashes and louder beeps that progressively alerted you if you fell asleep or were distracted for an extended time. In addition to those safety features, the internal camera in the Tesla could confirm that you are indeed watching the road when Autopilot is enabled. I was surprised to hear that this feature was not already enabled in Tesla cars. For the Cadillac auto driving system a camera and lights in the steering wheel constantly monitor your face to confirm that you are watching the road, or it will automatically disable the auto driving control. Unfortunately these are measures required today as the auto driving systems improve, and to prevent lawsuits for those drivers that ignore the stipulations of using the system, and get into an accident.