It's still misleading, because the miles driven with Autopilot are only a subset of total possible miles, and specifically are a _smaller_ subset of total possible miles than "normal driving".
To wit, if Autopilot is unavailable or disengaged because of poor weather/road conditions, a human still has to drive those miles. Autopilot gets the _best_ conditions to show its abilities. Humans get all conditions to show their abilities.
The question is "how did human drivers do driving the same miles, at the same times, as Autopilot", which is impossible to calculate.
As I said, whatever the reason, there are less accidents with Autopilot, than without. Autopilot is a convenience feature.
The question is: Are you willing to accept only 33% less likely hood of an accident with autopilot engaged as compared to when you drive on your own in not Autopilot safe conditions?
Do you use Uber knowing that their average driver will be ... well ... average, or just somewhat better than average? Knowing that the average driver baseline is 500 000 miles per accident?
He has a point, right? There's a possibility of clear sampling bias: if there are X miles that are safe and Y miles that are dangerous and autopilot can only be engaged in the X miles, then it's not creating safety, but the partitioning will cause it to appear to be safer than the human. If the partitioning had been done without autopilot the two partitions may show similar behaviour.
For an analogy, you've got two surgeons, one who only takes cases where he is extremely confident he can operate successfully, and one who takes the cases no one else will. The first loses 1% of his patients on the table, the second 20%. Which person is the better surgeon?
To wit, if Autopilot is unavailable or disengaged because of poor weather/road conditions, a human still has to drive those miles. Autopilot gets the _best_ conditions to show its abilities. Humans get all conditions to show their abilities.
The question is "how did human drivers do driving the same miles, at the same times, as Autopilot", which is impossible to calculate.