Well, it DOES work for me on a regular basis.
I guess it depends on the situation.
The advantage with only one point is that it will not screw up the image distortion, which happens easily with 3 or more points.
Plus it is a relatively good effort to effect ratio, which can get out of hand when placing more CPs. Very often in my experience it only moves the problem to a different area of the model and it is hard to find a point to stop.
With one point, it either works or not and if not you can still pull the plug or go back and take more images…