Vaping itself is a habit. Just like smoking is. It is the hand to mouth, replacement for drinking, eating, stopping, resetting, action that is the habit.
For many people that is harder to break than the nicotine addiction is. In any given cigarette there are additional chemicals including vanilla. Vanilla is in there for the same reasons Macdonald's put it in their cooking oils - it is just about the most addictive substance going. Benign, but useful.
Vaping is still being shown to be less harmful than cigarettes. Not harmless but less harmful.
All the complaints, armchair psychology etc, neglects much of the science. For example: vapers drag more often - yes, because they can vape more continually than they could smoke. So they self medicate differently. Less nicotine, more hits, keeping brain levels more constant. Less naggling demand and 'binge' behaviour.
I was a smoking cessation counsellor for 20+ years. I saw the difference vaping made to almost every client I had who turned to it. Skin, pallor, smell, measurable health indices, finances, etc etc.