We all aim, every time, or we don't hit. With sights and gapping we are using a point of aim, of some sort, be it the sight pin, or the arrow head.
Instinctive, which is just a name, that's all, there is nothing instinctive about it, is a matter of training. You shoot enough and train enough to know what the sight picture should look like. If the deer is this big there should be this much space above or below it etc. We aim using the whole sight picture, or we gap shoot, or we use sight pins or cross hairs.
Pretty obviously, if you are using a sighting device of some sort, the average Joe will likely shoot tighter groups. Why don't we all do that ?
Well, why don't we all shoot magnum rifles instead of sticks and strings ?
We all make choices, based in part by peer pressure, and (hopefully) in larger part by our own wants, needs, and experience. I like shooting what and how I do. I shoot well enough to accomplish my goals and make me smile.
End of story
CHuckC