Cigarettes aren't the best treatment for anything and the potential benefits never outweigh the harm but cigarette smoking treats some types of ulcers, colitis, and a few other lower GI issues. It may also prevent or reduce the severity of Parkinson's Disease, Alzheimer's dementia, endometrium cancer, uterine fibrosis, and endometriosis. It also negatively correlates with DVT and may make you more likely to survive if you have a heart attack.

https://pubmed.ncbi.nlm.nih.gov/8746297/

Gonna have to bite and ask what very specific scenarios smoking could be healthy?

For those times when someone points a gun at your head and says 'smoke this or die.'

Probably should've said "nicotine" instead of cigarettes because the benefits only come from the nicotine. Nicotine is a mild stimulant that's scientifically shown to have mood-boosting effects, even on non-smokers and can help relieve high blood pressure. Obviously it's not the best at either of these, but those are some medically beneficial side-effects.