Every smoker is a morally compromised addict. Some more, some less. I will die on this hill, and my tombstone will say: "Here Lies Rex, He Really Fucking Hated Smokers."
However, this is fiction, so I guess it's meant to make Kusanagi seem "mature and refined". And it actually... kinda works lol. For a moment there, I felt I wouldn't mind her mouth tasting like charcoal.