Smokers, as they die young but not so young as to reduce the labor force, save money rather than cost money. Quite a bit of money, actually[1,2]. People will of course die anyway and treating them of whatever cancer or heart disease they get when they are older also has costs.

You can make arguments against smoking (it's not good to die prematurely of lung and heart disease) but these financial arguments aren't valid.

[1]https://www.nzherald.co.nz/nz/smokers-save-govt-cash-says-re...

[2]https://reason.com/2012/11/21/want-to-save-health-care-costs...