With addiction, if amount of alcohol is increased, one becomes mentally impaired. With smoking, this does not occur.
As it is mentioned above for some, smoking is haram. So no big difference for some.
Alcohol in small amount has some health benefit but over the long period more damage to body and mind. Depends on the person though.
Alcohol is strongly addictive physically and smoking is also physically addictive but not as much as alcohol.
Alcohol strongly changes the personality or judgement of the person but smoking does not. Or if smoking does, then it is not so obvious.
Both alcohol and smoking are started once a week, and then gradually more often.
We do not know if nicotine was so common in arab areas as addiction. None of other religions specifically mention nicotine being forbidden.