Although I think that the libertarian principle has shortcomings as the final epistemic mechanism for civil jurisdiction, nevertheless it's a helpful mechanism in many cases, and I really cannot think of an issue to which it more obviously applies than this.
If you want to ban tobacco from public places, because some citizens don't want to choose between public places and smelling others' tobacco, fine. I disagree, but I can understand the logic here.
If you want to ban tobacco from being smoked inside a residence where minors are resident, fine, I disagree, but I can understand that logic, too.
But there are only two principles on which you could you ban an adult from smoking tobacco in a non-public, outdoor place (like his back yard):
His own health as an end in itself, or else his own health as a burden on tax-funded health care.
You can't say (as you could say in the case of currently illegal drugs) that he might be dangerous to other citizens while under the influence of tobacco. Nobody has ever claimed that.
There is much more justification for banning alcohol than banning tobacco. People under the influence of alcohol sometimes kill other people, so you could make a (strained) libertarian argument there.
But there is no such argument for tobacco.
If you keep it out of public places, and away from minors indoors, then it literally cannot impact anybody but the person using it (or tax-payers via public health care).
Whether health care should be funded by taxes is a different question which many of us will have strong opinions on, but let's just grant for sake of discussion that that dynamic isn't going to change any time soon:
Either way -- whether the concern is with or without regard for a centralized and enforced safety net -- this kind of legislation opens pandora's box:
By either of these rationales, we are now ready to begin legislating against anything the science de jour deems detrimental: alcohol, red meat, confections, etc.
Heck, we might as well alot people a certain number of calories which they are permitted to consume per day, based on each commrade's height, age, and level of activity in the service of the commune.
Let's be real: this kind of dystopian policing really could lower the burden on tax funded health care. And it really would be evil. So maybe this is an opportunity to go back and check some more basic assumptions.