No it isn't. As the article implies, the number of miles driven, or even the amount of time driven, isn't a good estimate of AI quality. The best standard is the number of unusual events that the autopilot could handle without human intervention.
I've had 30 hours of driving in a Tesla, and I had to intervene 6 times, twice with no warning. That doesn't mean that Autopilot isn't a useful tool, but it does require operator diligence.
When I said that it is pretty good, I base it solely on the fact that my friend is still alive, even while driving 6hrs per commute mostly on autopilot. I will have to ask him how often he has to intervene (mostly highway). But I do know that he has been watching a lot of Netflix during his commute... so your mileage might vary.
I've had 30 hours of driving in a Tesla, and I had to intervene 6 times, twice with no warning. That doesn't mean that Autopilot isn't a useful tool, but it does require operator diligence.