I'm not trying to convince someone to quit; that's up to them to derive enough motivation to do so on their own.

I'm just pointing out that their disgusting habit affects everyone around them, if it's not killing them through second-hand smoke.

I say this as someone who used to smoke 1–2 packs a day, and WISH that someone told me that I smelled as bad as I did. To me, smoking was never about impacting other people, so having known that, I would have at least been more mindful.