I play with my chin, ever so slightly, above my cue.
Like Pangit says, "I use my cue like it's a rifle."
I feel it gives me an advantage on many shots.
I've seen everything in my day.
I guess it's all about your comfort zone and how you learned to play.
In my defense. I played three cushion for a period of several years. It's a game you use a more powerful stroke, we didn't have heated tables or fast cloth, it was difficult getting several rails.
Then I went back to playing pool again.
I was still playing upright and I really struggled. My wife took pictures of me playing that way and I saw I was way above my cue stick. I got down to where I am today and played at a very high level for many years.
When someone has doubt as to whether or not they can see a shot they get down real low to look at it. It gives them the best perception of whether or not they can see it. So why not shoot from down there?
I to have seen many great upright players.
Just my thoughts.