I don't disagree that it's not the best of comparisons (and I wonder if a better one could be imagined + implemented...). But still, it's not like we turn on Autopilot/FSD only "on empty highways", far from it! Certainly it's a tool where the user needs to learn its strengths and weaknesses and use it accordingly, but it is useful in so many more situations than not, that it's also not a terrible or meaningless comparison to make!

Anecdata: Almost all (95%?) of my highway driving (Europe) is on Autopilot. I don't even enjoy doing the driving myself any more in those situations where I know that Autopilot is doing a pretty good job. In particular, Autopilot does a better job than I can in conditions of heavy snow / rain / otherwise poor visibility conditions. I feel a lot safer being the operator than the driver in those instances! (The alternative would often be to slow down by a significant amount, and/or use up more of my focus/attention, leading to either less safe driving or forced breaks.)