Then it turns out that nicotine use was self-medication and now you can't use any of a new class of drugs being developed that are all based on nicotine. OOPS
Nicotine has been far too politicized. It is practically impossible to find proper research. Most of it conflates smoking and nicotine use. Most of the really nasty effects of smoking are from the many other things in cigarettes, not the nicotine. There is evidence that that includes much of the the addiction. Practically everyone who has switched to e-cigarettes has noticed this. Even though the e-cig is giving you as much or even more nicotine than the cigarette, it somehow doesn't get rid of all the craving at first. There is a definite 3 day to two week period before the user is comfortably on the e-cig. A while after that, most users find that they want the e-cig but not in the urgent way they used to crave a smoke break. Many, if not most, choose to reduce the nicotine level in their ecig even if their intent was never to quit nicotine.
A leading theory is that the harmaline (an MAO inhibitor) found in cigarette smoke is responsible. It potentiates the addictive effect.
Once the tar, particulates, carbon monoxide, and most of the nitrosamines are eliminated from the delivery mechanism, nicotine use is much more benign and for some people, even beneficial.
All of this would be much better known if nicotine wasn't such a political bogeyman.
Some of the nasty products of combustion may be contributing also. Vaporizing marijuana has a very different compared to smoking (burning) it. When marijuana is burned, Carbon dioxide, Carbon monoxide, benzene, toluene and naphthalene are produced. Some of these (or a combination thereof) contribute highly to the "couch lock" effect, which different users either prefer or dislike. When you vaporize marijuana, these compounds are not produced- a "couch lock" state is substantially more difficult to achieve with vaporizing marijuana, and therefore the effects of vaporizing/smoking marijuana are markedly different.
I am not a tobacco user myself but it could be that many of the tobacco combustion products contribute to the pleasure of smoking tobacco.