Some people do consciously use BHE, but there are a lot of people that take advantage of it without knowing it because their natural bridge length falls on, or very near, the pivot point of their cue. Personally, I play with an LD shaft (WD700), and prefer to consciously adjust my aim to compensate for squirt before I get into my stance instead of pivoting when I'm already down on the ball. That way, I can come down on the ball with everything (feet, hips, elbow, wrist, cue) in line with my shot and use the same stroke every time, just varying the speed.
I do the same thing for the same reasons but I try not to do this consciously. At least when I'm playing my best I don't have to think about it much at all. I absolutely abhor the idea of having a different lineup for nearly every shot requiring english. I really can't believe people play like that but to each his own I suppose.
Since I use this method, I would think the ideal pivot point of a cue would be one that falls right smack dab in the middle of the bridge hand and the grip hand. Then when you do this sort of air pivot you would have your pivot point in an ideal spot and it would be less cumbersome to deal with. Trying to pivot off of my bridge hand has always seemed unnatural to me. Having a pivot point right in the middle of the two hands seems like it would be the most ideal.