If you guys want to pay to read what appears to be simply a worked example of what each of two manuals says, far be it from me to judge.
I didn't have to pay anything extra for reading that article (well, beside the annual subscription), did you?
I thought it was a well constructed tutorial including very pleasing pictures, some factual info from Death Valley, and well-laid out and easy to follow text.
Perhaps an overkill for an experienced photoshopper, but surely appreciated by less experienced shooters, and as always quite inspirational for most photographers. Pointing out and documenting possible problems with missing parts of the sky makes for a good and practical example, and a good tip to capture a few extra frames while photographing the scene.
As you suggested in your second post, adding more material around the edges is always a good idea, not only that it alleviates the need for content-aware fill, but also it should improve the perimeter sharpness by using more data from the central part of the lens. If I find myself in that part of Death Valley in similar conditions, I'll remember examples in this article.