seriously, try this:
toss the balls out onto the table... shoot every shot with NO practice strokes - and see how many shots it takes to clear the table.
toss them out again and take at least 3 practice strokes before hitting the cb - count the strokes.
i'm pretty sure the rack with the practice strokes will give you a lower number of shots to get out.
theoretically, you make sense. if you have a straight stroke and know the contact point, why take practice strokes... but we aren't robots and we have finer movement ability, so those pre-strokes actually get us in line - as opposed to just being in the area of the line.
Im just learning how to play this silly game but I do want to say one thing. Your feet and cue line get you into line. Not your practice strokes. and when you know your in line with out practice strokes, your not second guessing your self. If your body is inline on your shot, you can feel it. You should know if your going to make that ball when you bend over the table. I would not want to rely on my practice strokes for any kind of aim. Your body should aim not a moving arm.