Something that probably took me way to long to learn is that sight alignment exist along a continuum. At one end I have zero use of visual reference to shoot, and at the other I have perfect sight alignment and an intense focus on the sights. In between is everything else.
Up close at or near contact distances, my need for referencing the sights, or any visual reference at all, may be zero. At 50 yards, my need for referencing the sights is pretty high, and in between is everything else. A demonstration that really drove this point home to me what a demo Mike Seeklander did on an IDPA target. He intentionally misaligned his sights to show where the round would hit. It barely hit outside the -0 zone from 7-ish yards with the front sight post nearly all the way outside the rear notch on an M&P 9. The only way to find out what your gun and sights will let you get away with is to go try it. Just remember that you still have to execute good trigger control to get good results.
When I am shooting at a closer range target, my front sight is basically never sitting still. It lifts with recoil, drops back into the rear notch, or close enough to it, just long enough for me to see it is there and then lifts again because I have fired another round. This is one of the reasons why I like the Ameriglo front sight on my chopped Glock 22 and the plain black rear, it is really to see the orange circle floating around in the rear notch.
A good example of the front sight never really sitting still is the video below. The gun is pretty much always in motion, and I am not even that good. The target is a USPSA A-zone at 7 yards.
This is an example of when a more precise and more refined sight alignment is needed, along with very careful manipulation of the trigger so as not to disturb the sights.