I am an NRA instructor so I can tell you that the NRA beginning classes do spend some time on this subject. For new shooters, learning about it just introduces a complex topic, but it does prevent some unnecessary frustration for first time shooters that have cross dominance and can't figure out why they can't use the sights.
Other than helping new shooters to get settled in to a practice routine, those who have had some experience don't give it another thought. There are a few ways to go on this, assuming that you are not personally afflicted by a severe hand-eye coordination condition. First, the head can move side to side to aquire a sight picture with the dominant eye. Turning the head left or right can also get you there. New shooters should actually close one eye because they have not settled on a system that works for them.
Speaking from a personal point of view, I was able to overcome cross dominance problems by practicing with both eyes open, while at first checking which sight picture my brain should select. People without this condition have already trained their brains to do all this. But it only takes a short time to "retrain" to get the brain to concentrate on the correct sight picture. It works, doesn't require drugs or alcohol or the help of a neurologist. So in short, fussing with cross dominance is, in fact, a waste of time except to get a new shooter squared away and capable of practicing.
Wireman