As I said elsewhere, that may be a "corner case" in California, but anyone driving around on snow-covered or salted roads in the northern half of the country knows that low contrast between the lines and the road surface can be the rule rather than the exception for about 6 months out of the year.
Of course, maybe there's a distinction there that I don't know enough to recognize, but Elon's discussion of it on the most recent investor call wasn't exactly heartening. He basically said, "yeah, the AP software does a great job if there are other cars on the road, but it's not as good when there aren't other cars"--in other words, as long as there is a human that the AP can follow, it's fine.
Which I suppose is useful? I don't know. I continue to be mystified about why anyone would want this feature.
Anyway, my guess is that the Model X will not launch with 6.2, so I am happy to bet that we will see the rollout of 7.0 happen no later than the first customer deliveries of the Model X.
Whenever that is.