Yes, cannabis can be habit forming. But as someone who has used both extensively tobacco addiction doesn’t compare to a cannabis habit. One encourages you to light up ten or twenty times a day and smoke a whole cigarette each time, from the moment you wake up until the moment you go to bed.
I don’t think I’ve smoked ten bowls in a single day in 30 years of blazing.
If you want to argue as to rather or not the burnt carbon in cannabis is carcinogenic I’d have to dig out some research.