Open stances allow the hitter to see the ball easier but causes more movement of the body. A neutral stance allows for a minimal amount of movement in the swing. A closed stance is used if the batter has a problem with stepping out, during the swing.
I was watching Yankees vs. Blue Jays spring training game the other day. 95% of the hitters had a slightly open to open stance. I think I saw maybe 1 closed stance. This should answer your question.
Every stance whether open or closed most of the time just before the swing ends up at a lateral position. Starts open but usually at the beginning of the swing its in the normal position. Take a look