Don't you mean 'purported beneficial effects'? Damage to the lungs is most certainly an 'effect', albeit a negative one. The way you wrote it, it reads as if something like lung damage is all in one's head, imagined (and I'm sure that's not what you meant?).
While I don't condone smoking, Wikipedia[1] summarized certain physical benefits of nicotine from specific sources (and I cannot comment on the reputation of the sources themselves):
>Nicotine is frequently used for its performance-enhancing effects on cognition, alertness, and focus.[40] A meta-analysis of 41 double-blind, placebo-controlled studies concluded that nicotine or smoking had significant positive effects on aspects of fine motor abilities, alerting and orienting attention, and episodic and working memory.[41]
[1] https://en.wikipedia.org/wiki/Nicotine#Enhancing_performance
How is "mental or neurological" not physical?