Well, I agree. He would be out of his mind to try and ban tobacco because it wouldn't work. Just writing down on a piece of paper telling people to stop doing something bad for them won't make them stop. You'll notice that I'm saying that if people stopped smoking, it would benefit the economy. What I never said is that the economy would benefit if smoking were banned. I said it would benefit if people stopped smoking. The amount of tax the government reaps from selling tabacco at exorbitant prices would be counteracted by the fact that people will be able to live longer, be taxed for longer, work longer and work more efficiently. People living longer shouldn't put strain on the economy, people becoming incapable of supporting themselves does. Could you please explain how people living healthier for longer could possibly burden the economy? I don't really understand.
What people believe doesn't concern me. But here's some facts for you: smoking is correlated to cancer, it weakens the immune system and opens the body up to opportunistic infections, it depletes lung capacity and reduces your ability to work efficiently for extended periods of time, and over all due to increased oxidative stress, it decreases your life-expectancy. And Harry Potter does not make people wiccan. You can't compare the two and pretend your analogy is a good one (it's not).
What you fail to see here is a principle - a precedent that such a measure would set - you're quoting health risks of tobacco at me - there are health risks to just about everything. Chocolate increases your sugar levels and excessive consumption can lead to obesity, diabetes, rotten teeth...Alcohol can lead to an addiction that will ruin your career and family life, it damages your brain cells, impairs your ability to drive...
The same logic can be used to ban virtually anything - I'm only using Harry Potter as a rather extreme example to illustrate it - as in, "where will it all end, this banning!". FYI, it IS a good analogy, if you see what I'm trying to demonstrate.
Second, regarding living longer + economy. I said it sounds strange and didn't go into it, because usually when you argue this point you sound like a fascist who's planning on killing everyone at the age of 60 or something. OK, people living longer is absolutely a massive burden to the economy - you say you can tax them longer - how do you tax over 60's who are retired and living on social welfare? Indirect taxation maybe, but on the whole not so much, especially when you compare how much money it takes to keep the old dears going. Nursing homes, medication, pensions.
The real strange thing is, do I therefore mean more people should lay down their lives through smoking-related illnesses in order to release the burden? No, of course not, let me just make that absolutely clear. But, the point I'm making is that getting rid of smoking, whether through voluntary quitting or simply banning it, will NOT just magically help the economy - the arguments for the burden on the economy are just as strong, if not stronger.