When you close one eye you loose your binocular vision. This includes depth perception which is necessary for estimating distance.
I would much rather my subconscious mind take over my shooting than my conscious mind. Too much going on surrounding me to give full attention to all aspects of shooting. I have had 2 instances back when shooting a compound bow that drew me to instinctive shooting. In one case I remember seeing the deer walk in, sniff the scrape I was sitting over, I remember standing, concentrating on the spot and beginning to draw the bow. My next memory was the bloody arrow sticking up in the ground. I don't remember my draw, anchor or shot. My subconscious mind took over, drew the bow, allowed a clean release and put the arrow where I was looking. Muscle memory is a big part on this scenario and you only achieve that with lots of purposeful shooting paying attention to form, draw and release.