I'm wondering, what makes a mantra particularly effective in treating physical imbalances? For example, the vajra armor mantra is supposed to be effective to treat the "404 diseases" - is this presumably because it repels the 8 classes of spirits? If this is the case, then wouldn't Dorje Drollo or Vajrakilaya practice be just as effective? Yet I know that accomplished Vajrakilaya or Dorje Drollo siddhas may still do vajra armor for "healing" purposes.
Another question is - in what case(s) is mantra sufficient alone for healing, and in what case(s) are physical medicines also required - how would a Tibetan doctor determine this?