Why Is Centering Less Importantant Outside The Us?

The SON preference has been well established by the majority of collectors in Norway since I was a kid. Stamps with LUX SON cancel often sell for more than cat val, and seems to be more important than centering over here.
And I am in that camp as well, simply love nice SON items!

To me centering is important but less so than presence of toning, short perfs and other obvious physical flaws. In my Canadian collection, I am always looking for good centering on the earlier issues but am a little forgiving on slightly off center stamps if everything else is perfect including the back of the stamp. A good example might be one of the George V booklet panes, some of which are becoming hard to find and I have bought a couple that were a little off because they were MNH and otherwise looked really good. I will not buy a scarce early Canadian stamp with perf flaws. Just a few thoughts. I should add that I am not that concerned about resale value; mainly that the stamps are pleasing to me to look at.

The SON debate doesn't matter much to me. I can appreciate a nice SON cancel but it is not something for which I would pay a big premium.