New Zealand has public healthcare. Around 5000 people die here per year as a result of smoking, which reduces any taxes those people would have paid had they not died, as well as costing tax payers for the time they spend in hospital.
The ban on cigarettes here wasn't to be an outright ban but one staggered over a number of years.
There's been a gradual decline of smokers in NZ over the years, so there is some evidence that such laws could be helpful rather than simply creating a black market.