i used to hang out with a opiate researcher. he was probably the most urine tested person on the planet. he understood pure heroin and, believe me, there is no better pain killer. like most illicit substances, the most dangerous thing about it is its illegality and the impurities introduced by the criminal element. in the presence of pain, it has no addictive qualities whatsoever. the trick is to limit the dose to pain management, both coming on and going off. its when people get high on it that the problem starts.
i agree with your take on it too, although opium is also abused for the same reasons heroin is.