Shafts have tapers.
Which part of the shaft is aimed ? lol
From my vantage point, I don't really notice the shaft having a taper. Sure, if I look down the cue from the end of the butt, I'll see it, but not while I'm down on a shot. Maybe my bridge is shorter than yours? But honestly, maybe you're over thinking it? If you want me to be literal, I guess you could draw a straight line in your mind from the joint, through the edge of your tip into the contact point on the object ball.
If this is something you're interested in, I would suggest trying it. If it's not and you don't need the system then no need.
All these magic aiming systems still end up to one thing.
You have to visualize the two balls colliding for cue ball control.
And some peeps will deny they don't do that, but I ain't buying .
This system, you have to know the contact point. From there, you know which way the cueball will be traveling. I'm not really visualize the two balls colliding other than just the exact point they should touch. From there, you draw a line from that point to the pocket (that's how you know the contact point) and a perpendicular line for the tangent line.