The shaft won't have as much influence as you would think because you are essentially hitting center ball. You are essentially trying to hit center cb, but favoring the inside just a hair. That way, if you don't go quite straight, you will still hit the correct side of the cb, which is just a hair, not a tip, but a hair of inside.
That is why he says "no spin", you aren't hitting it enough to the inside to put enough spin on it to matter. Now, the drawback is, if you can't reliably hit the cb where you want to, and you go for a hair of inside, you will be putting more than a hair of inside on it, and will get some spin. Then, the whole equation changes due to amount of squirt from each shaft, and amount of spin you actually put on it . Which, if too much, you will miss due to throw of the ob the opposite way.
Technically, even hitting a hair off center will put spin on the cb. But, it is so small that it is of little consequence. Basically, if you can't now hit center ball reliably, this is not going to help you because you will be putting english or spin on the cb. His technique is more of a mental trick than a physical trick. You just want to tell your subconscious that if you don't hit center cb, you want to favor the inside cb. You don't actually try and hit inside, or you will be spinning the cb. You aim for center, but favor the inside mentally.
Neil I think its more than just a hair maybe.I think the whole point is CJ is deflecting the cue ball to send the ob to the pocket,there for he is coming at the shot thick.(undercutting it )
The toughest part for some mite be connecting the balls.
Lets add in trying to hit off center a hair,that itself can cause all sorts of trouble.