“its not mutar on purim. its just accepted “
Whoa a bit slower…if you are smoking on Purim and Purim only then it doesn’t go into the category of Veshomartem Meod Nafshoseichem because 3 cigs a year will not do anything at all to your lungs.
But chances are that if you start on Purim your bound to carry on and eventually get addicted which is clearly and definitely ossur. So it might be Ossur to smoke on Purim solely because you will likely end up addicted but the actual smoking isn’t ossur.