We're still in the early days of self driving cars, and as much simulation and miles as they have, they're still constantly getting exposed to real world conditions that are new to them. The world is dynamic, so this will always remain true.
It remains to be seen where we'll converge on capability, incident rate, and acceptance.
I think we're already there with Waymo as the example. We may later choose to diverge from this now-accepted path, but for the moment we have a blueprint, and fixing edge cases with a software update is apparently acceptable, if you just look at all the Waymos operating legally right now.
In that context I think comparing it to the average human driver makes a lot of sense, because even if you personally are an even better driver, or even if human drivers are better at some specific things, we have more than enough data to show that Waymo reduces accident rates overall in their current rollout.