Most SEP instructors seem to teach attitude for speed so I only tend to introduce p'n'p when converting people onto complex types, to twins, or if they ask to do it on a BFR.
(Small error in the OP - the aiming point is held constant in the windscreen until the flare; the power is adjusted to maintain the correct speed - the airspeed is not "constantly varying")
I do not quite understand why point-and-power method is more suitable for complex types (what does complexity has to do with the flight path?) or larger airplanes.
If you hold the aiming point constant on the windshield wouldn't it result in a different glide path angle every time? (depending on where you initiate you final descend)
It seems to me that to get back on the 3 degree glide (in case of being above it) one has to point the airplane short of the aiming point to get back to the glide path first and then re-aim for the 3 degree.
Am I wrong?