On a slightley adjacent topic, wouldn't it be more usefull to train Iron Shirt as oppossed to Iron Palm. From a morality point of view being able to take several solid strikes is extremely advantageous and would seem to be much more "merciful" to allow you to control the situation as opposed to just breaking someones face off or rupturing organs.
While I would love to train Iron Palm, just for the sake of training such an esteemed art, I can't honestly think of a situation in which Iron Palm would benefit me in a day to day scenario that the nei gong and wei gong present in of TCM doesn't already accomplish. I'm just thinking of practicality here. For someone wishing to preserve knowledge, I can completely see the reason but how many practice for completeness and preservation and how many practice for ego? Not saying everyone does, but thats why there is a TV show on now which just has dudes breaking stuff with there bodies.
While I train to be a better fighter, the more I train the more I realize I'm training to be a better human being. And in the end, if I want to kill someone, there are more efficient ways than spending years plunging my hands in pebbles. Thats why they make firearms.