Herman,
I do strive for symmetry and a attempt to get to a 1/16 but only because I have devised a method that makes it as easy to do that as it is to strive for accuracy only to a 1/4 or 1/8.
BTW, I am not actually measuring from ear to speaker, but rather from a center mark on my chair to each speaker. The chair has been set equidistant to each speaker and marked with tape so I can put it back when it slides on the carpet over time.
So the whole technique rides on a assumption that my ears are equidistant because I am centered in my chair. Which they are not, consistently. I still prefer doing it. I can’t see how it hurts anything—and I know you didn’t say it did.
I will be visiting a dealer I’ve done business with in a few weeks. He is a very experienced guy and a fairly newly-minted Wilson dealer. I texted him once and he replied that he was in the middle of learning the Wilson set-up method. I hope I remember to ask him to address the point you make. I had no idea anyone aimed for accuracy greater than a 1/16 and have been aware of the potential futility of that, but 2/10,000’s of an inch? Wow.