Mine was meant to be humorous too, so if my snarky attitude came across wrong, apologies ?
Concerning "resolution" IMO there are two ways to cut it: numerical/objective resolution, and perceived/subjective resolution. One can be defined by calculating how many practical points of information are in your image (in our case, pixels). The other is based on how much detail the human eye perceives, and with anamorphic especially, the two are at odds.
Objectively, you may say that by stretching a digital file by a factor of two, you have halved your numerical resolution. It is half as sharp. The catch is, though, top to bottom you have lost no sharpness. The image still has the same number of "lines" (in the case of 4K, 2160 lines). At this point, the temptation is to say, "ok, I may have lost half my resolution, but not half my sharpness. I've probably lost 1/4 of my sharpness."
But subjectively, as the eye sees, the loss is even less. Because your vertical lines of resolution are all still there, you still have very near the original sharpness in many parts of the image. The eye picks this up, and the brain is frighteningly good at filling in the rest. Add to this that the images are changing constantly, and (all else being equal), you won't loose much perceived resolution at all over shooting spherical, even at 2X.
The by-far most important thing has already been stated though: If you're delivering to web it doesn't matter. Most web watchers are in their phone or tablet, most of which are not 4K, or even 1080p. The minimal loss in sharpness/resolution won't even make it past the compression to be honest, but the stylistic differences in the image will. That's why I prefer 2X, as it can be more pronounced. But 1.5X also looks great, it's just a preference.
