[Al Skierkiewicz]

Kevin,
You are right but the power is concentrated in a very fine wire which for most purposes needs to be insulated. If the application calls for a sustained period of constriction then the heat needs to be dealt with. Add to that the possibility of using more than one to increase the pull and the heat sources add to each other.
But imagine the possibilities. A few short peices lifting a few pounds over a short distance. It would take a sizable motor and tranny to do the same. Think about mirror adjustment, lens alignment, vents, etc.