Former heavy smoker here, quit two decades ago. It creates a strong craving, which briefly supplies pleasure when you appease it. It provides (or at least used to) social connection with other smokers, particularly at “smoking breaks”.
And it gives you something recognizable to do while waiting for something. Rather than sitting there, staring out with a stupid look on your face, you instead sit there smoking a cigarette.
It’s an incredibly difficult addiction to break, it’s expensive, and these days identifies you as either very old or more or less a loser. Avoid, avoid.