Uh. Some experts on this board have espoused pitching from your toes as a drill as part of learning....
Uh, yes they have and just like Damon S said, it was in response to a particular need for a specific pitcher. My DD is one who benefitted from his approach to help her get the feeling of "staying tall" through the pitch and not sitting/collapsing during the stride.
The mark of a great PC is the customize their coaching strategy to each athlete's needs, not make it a one size fits all approach.