In my mind, several things happen.
First, a half inch off at ten yards can be a LOT off at longer ranges, just like any projectile.
Second, As you get farther, it is more difficult to accurately assess yardage AND it becomes more critical due to the rapid drop in flight path.
Third, I can see pretty well at ten yards and can pick a small spot to aim at. At twenty it is more difficult and at longer distances yet, it gets to the point where I cannot do that and shoot at an area, not a hair. Built in inaccuracy.
If your eyes are awesome ( mine were) you can do it farther than most.
ChuckC