I'm not sure. When I was in residential there were some smoking social workers/nurses, and I didn't think less of them for that.

However, if my current T or pdoc were to start smoking or say they smoke.. I guess I would feel weird, because I really can't see them smoking. Maybe I'd also feel betrayed, because I've been seeing them for 4 and 3 years respectively and to only now find out..
Also, as they are the ones who actually treat me and try to convince me to make healthy choices, I'm not sure how serious I would be able to take that if they smoked. But maybe that wouldn't be the case.

For a new T, it would probably depend on the whole picture. A bad therapist I might complain about their smoking, and a good one I might not mind.
It sounds really silly, but things work like that sometimes.. I am a survivor of medical torture. When I was inpatient, a fellow client asked me about my experiences with THAT facility because he might be getting a referral there.. I hadn't really started to dig up that trauma though, so when he asked how the people were, I complained about their inability to use our country's language correctly. Then I didn't know what else to say. A social worker sat at the same table and she said: "They also left you with a severe trauma, didn't they?" (or maybe she said: they also hurt you a lot, didn't they? or whatever her words were) which sort of was the light bulb for It's not the grammar mistakes that bother me.