I'm generally pro legalization of drugs, but will say this is likely to be much more effective than the war on drugs ever was.
You don't outlaw possession, just the sales age. You'll see significantly fewer new starters as time goes because after 20 years 40 year olds that can buy wont be bothered to support fresh 18 year olds looking to start a new habit or whatever. The ones that really want to start can buy from abroad without any form of punishment.
I think it's different because I don't think anyone turns to their first cigarette looking to try and attain some new feeling. It's usually one of those things like... My friends were so I grabbed one from them and blah blah.
I would say I'm for the progressive increase in age, and I wrestle with my own hypocrisy seeing that I support legalizing other drugs. But maybe that's rooted in the basis that I've never had a pothead or dude on shrooms negatively impact me. Cigarettes however--littered everywhere, get smoke in your face, etc