Smoking???

I was with a friend having drinks at a restaurant with open windows on the street. On the other side was a bench. This man sits on the bench with a cigarette, talking on the phone. I see the smoke go into my friends face and I wonder why she doesn't react. I call over the waitress to tell them a man is smoking and he turns around and ask if there's a problem. I say that he is smoking right next to us eating. He said the smoke is water and explained that he was smoking a vapor cigarette, no smoke, no nicotine.

That explained why my friend didn't react, but I was still a bit confused. I asked him why he was "smoking" it, was it because he was trying to quit? He said he never smoked cigarettes. I asked him "then why?" and he said "I like to puff."