Yes. With a ghost ring peep sight on a Ruger Super blackhawk and both eyes open I could hit 6 for 6 on gallon milk jugs, offhand at 50 yds. Try hitting running running whitetails with a handgun and one eye closed....much tougher with one eye closed.
For you one-eyed shooters....do you need to close one eye while driving to keep your vehicle in its lane?
I am right eye dominant and shoot a shotgun with both eyes open. I was a competition pistol shooter and I closed my left eye. You have to because you are focusing on the pistol sights and it's too difficult to center the out-of-focus bullseye if you're seeing two of them.
Of course, that's with iron sights. I never shot with optical sights. I was NRA Expert. That was the second highest class below Master.
I shoot everything with both eyes open, shotgon, scoped rifle, pistol, bow, hell even a slingshot when I was a kid... I tried one eyeing a rifle several times, but found myself feeling tensed up, so I just went back to 2 eyes open.
Maybe just me, but I feel extremely more comfortable (and much more accurate) with both eyes open. My 2 cents...
I shoot both shotgun and pistol with both eyes open. I shoot pistol both left-handed and right-handed. I can't do that with a shotgun....nor a baseball bat, bowling ball, or golf clubs. But I can do it with a fishing pole or a tennis racket. I do all of those with two eyes open.