You just looking to start trouble or what? LOL
Well if the question is "Why do people smoke?" then it's because they are addicted, if they care to admit it or not. If the question however is "Why do people start smoking?", well that's entirely down to each individual who smokes.
I started when I was 21. Had been opposed to it my entire life after seeing how bad it made my gran, and I still to this day believe that the smoking was a factor in her death (Brain aneurysm, basically burst blood clot, and as we know smoking doesn't do your blood flow much good!). I swore I'd never smoke.
The reason i started was rpetty daft. I was in a play and the character I was playing smoked. It was only 3 cigarettes per performance for a week so didn't think it would be that much of a deal. But after a couple of rehearsals I found myself sneaking off with the "props" at the end and became addicted. Then for a long time I didn't really have a reason to stop- I didn't care too much about the health issues, hanging around outside with the smokers was always way more sociable and I actually made more friends and enjoyed myself by that type of socialising. At work most people smoked so outside to the courtyard we'd all go, so many of us smoked even the non smokers joined us outside otherwise they'd be like two of them sat at the lunch table. And before the smoking ban came in there was a lot of people smoking in nightclubs and "Got a light?" was always a great way to start talking to women. But the main reason I didn't stop was because I was addicted.
It took me several attemps before I finally stopped smoking cigarettes and can honestly say I do feel better. I don't have as many pains in my chest, I can breathe easier and myrisk of lung cancer/ heart attack are both falling.
But simply to answer your question in the way you word it, we smoke because we're addicted not because it's appealling. But a better question to ask is why do people start as there are as many different reasons as there are smokers.