In many stressful situations, the sights are seldom used as anything more than direction indicators. They may be aligned for accuracy, but the shooter usually wants as much of the image and surrounding area as visible as possible. This is especially true for up close and personal shooting.
The shooter in such cases will practice using the sights as "indicators" to save time getting on target. At closer ranges, pinpoint accuracy isn't usually an issue.
For shooting distance or when pinpoint accuracy is required, and there is time to acquire the sights, then an individual might like them to be further back.
Open, tangent, notch sights are a different ball game, as your eye doesn't automatically center the front sight in a "ghost" ring.
Some folks can and do learn how to focus and acquire sight images very quickly. In my case, that wasn't one of my areas of expertise, so when stressful situations were happening, up close, taking the time to properly utilize the sights wasn't an option.
I've spoken with individuals who only used the front sight hood while looking over the rear sight when shooting under stress.