Just what do you think is going to happen to the index figer tip when you try this technique on a revolver and the finger overlaps the cylinder gap?

I've seen this so called "point shooting" technique and tried it on a semi-auto.
I don't care for it:
No control in one-handed shooting.
The afore-mentioned revolver problem.
Inferior control for precision shooting.
Possibility of interfering with slide.
Reduced control of gun for reloads.

Generally appeals most to people who have not learned proper grip and trigger control, and are yanking the trigger. Provides a change to break the "yanking" habit.