I think that advocates are right in that, once the kinks are worked out, they will be far safer than human drivers.
At the same time, I think the implications lead to a lot of dystopian implications for cities. Like, a properly tuned self driving car will never hit a pedestrian. So pedestrians in cities will learn they can safely step out into the street even in oncoming traffic. But this will cause the car to swerve and slam to a halt, which us a bad UX for the passenger. Enter: automatically reported jaywalking offenses powered by car cameras and facial recognition technology.
I mean, zoning reform needs to happen before transit is a viable option. Miles and miles of low density sfhs and strip malls will never be able to be effectively served by transit because a transit system can't possibly be efficient enough to both serve a reasonable number of people and get people where they are going in a timely fashion. Its just geometry.