While a glance at comparative national mortality statistics might make a compelling argument for the more general health benefits of smoking (Africa has had for decades the lowest rates for both smoking and life expectancy), I am more concerned with the specific area of mental health. In first-hand observations among smokers, non-smokers and ex-smokers, I have noticed that smoking is the only reliable cure for neurosis, and that people who give it up quickly become strident, interfering and unhappy.
My Romantics tutor (a non-smoker) was a man who travelled a lot. He told me once (we were sitting in one of the most beautiful spaces ever created: il Campo, in Siena) that, if he could, he always chose to sit next to a smoker on the plane because they were invariably more interesting. [I can't quite see the connection between my reminiscence and the claim made in the quote, but I let it stand anyway because some things need to be said.]