Gwern has a pretty good post on it:

https://gwern.net/nicotine

Intuitively, why would you chew nicontine gum to stop smoking if it was just as addictive as cigarettes?

this article isnt as relevant as when it was written. eg regarding price, cigarette taxation has skyrocketed in certain countries. furthermore, the depicted studies were performed prior to the proliferation of disposable vapes - i somehow doubt that the idea of infinite nicotine on tap was accounted for. as to your question, some individuals find cutting down to be easier than cold turkeying. personally i opt for the latter, although this strategy should not be universally applied (eg. alcohol withdrawal may induce seizures). at the end of the day i find smoking (not vaping or gum) to be a net neutral - controlled motivation, treatment of schizophrenia symptoms, and neuroprotectivity are balanced out by addiction potential, shortening of lifespan, and reduced red blood cell count.

Presumably because you aren't turning your lungs into jerky. Sounds like a strict improvement to me