I've always felt the 6'oclock hold was maybe best for paper target shooting at a known distance, because the front bead could cover up the entire target and you may not be sure where you are aiming exactly.
However, when I put the front bead on an animal, that is the spot I expect to hit. It's a little rough in the real world to try to estimate the 6 o'clock hold on a running deer plus amount of lead. I feel the 6 o'clock hold is for paper punchers only.