My SO and I both used to be militant chain smokers, and we both found ecigs/vaping helpful for giving up cigarettes. It can certainly help with the psychological addiction that a lot of smokers have. There are also different strengths of 'juices', so one can slowly wean oneself off nicotine by vaping with gradually less nicotine. After a month of ecigs and no analog cigarettes, my lungs felt tidy and clean (no coughing up weird stuff after exercise.)
I no longer vape or smoke, but still use nicotine through other delivery methods. From time to time, I'm having nicotine while riding a fancy road bike in full kit.
