The "phantom move" is a balance drill, NOT a way to ski. Even Harald sez "lifting is learning, lightening is skiing".
After working with PMTS drills myself, and working with students, there can be some problems with the drill, and people can get bad habits from it. If it's done incorrectly.
Only focusing on the fact that it is "one footed skiing" will not get the skier there.
The example given about the funny upper torso stance to balance on the stance foot while picking up the free foot is a perfect example. Why is that happening, hmmmm? So is slapping the free foot against the stance foot and displacing the stance ski to make the turn...
Like any GOOD skiing drills and/or progressions, these things must be demonstrated and taught correctly to achieve the desired results.
Sometimes skiers can and will overdo a particular drill, because the drill itself is misunderstood as "THE way to ski".
A musician taught in marching band with sheet music may NEVER get to the point of playing jazz. One is a very "set" way to play, the other is improvisational.
I personally think the mountain is more rewarding when I play jazz with my feet, instead of martial tunes, or even rock and roll...