Thought I'd chime in with a beginner's view point:
I only started a season ago. When I started, I unfortunately only had my gf to go with and learn from, and she didn't know much at all (still doesn't
) First day I was doing the falling leaf technique on accident. I knew immediately that getting used to this would make it harder to link turns so I forced myself to control my direction better into what I think Snowolf has been defining as Garlands? Either way, I noticed I progressed MUUUCH faster once I eliminated it. Needless to say, I progressed "scary fast" as my friend put it, but my gf STILL to this day has a hard time linking her turns and getting out of the falling leaf habit.
Over the summer I've been trying to do online research and such to learn and practice for next season. In the process I found that the "falling leaf technique" was an actual move, not me being some n00b that can't link a turn...and all I could think was how detrimental this would be to actually teach someone. Personally, I think it helps more with getting comfortable transitioning from switch to normal / vice verse, or to slow down on a slope your not comfortable with. They remind me of toe/heel slides when bombing down hills on my longboard, except those require skill to do haha
Edit: Thought I'd also throw in with Snowolf's last point. Learning steeps on the black diamonds, I agree, being able to accept the speed and nose dive to initiate the turn is essential. I kept washing out with leaf like symptoms because I was too scared to gain too much speed (though I also realized I need to detune my edges), but once I was able to accept the speed and nose dive for a second, my game of control was brought up to a whole new level. I, being in my first season, was now bombing and racing my experienced friend down black diamonds.