https://www.ncbi.nlm.nih.gov/pmc/art...6/#__sec3title
Importantly, in the LHS, smoking cessation was associated with a slower decline in lung function and reduced risk of hospitalization and total mortality. Participants in the special intervention group plus a placebo inhaler, who became sustained quitters, experienced a forced expiratory volume in one second (FEV1) decline of only 34 mL/year. In contrast, those who continued to smoke experienced an FEV1*decline of 63 mL/year.7*Thus, smoking cessation nearly halved the rate of descent in FEV1*in patients with mild to moderate COPD. Smokers who quit and then took up smoking again had FEV1*declines that fell somewhere in between that of sustained quitters and continued smokers.7Interestingly, female continued smokers experienced a faster decline in lung function compared with male continued smokers for the amount of cigarettes they smoked.16*However, female smokers experienced larger gains in lung function when they stopped smoking compared with male quitters.6*Smokers who quit and re-initiated smoking at multiple times experienced a slower decline in FEV1*than continued smokers, for the same number of cigarettes they smoked.16*Together, these data suggest that smoking cessation significantly reduces disease progression in mild to moderate COPD and that even having multiple relapses is better than continued smoking in terms of disease progression. Tobacco treatment is particularly important for women, who appear to have increased susceptibility to disease progression with continued smoking but also derive larger benefits with smoking cessation compared with male smokers.
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Slower decline, and reduced risk of hospitilazation and death. That is not the same as healing, but also doesn't say "there is no benefit"
This is a study of patients with COPD.