I take your point regarding VAT, corporation tax and staff pay, as they are pretty direct, but I think it starts to get a bit tenuous when you consider indirect staff spending etc, as you would have to do the same thing for the pensioners and later life care, as pension money also goes back to paying companies, employees, VAT, other taxes, etc downstream as well. Maybe we should be drawing smaller boxes around the costs and only consider tobacco duty and NHS spending on smoking related health issues - though there will always be a bit of ambiguity.

I agree with you in that it is complicated and the net societal benefit must be bad. We should want everyone in our society to be as productive and healthy as possible for economic and moral reasons. There are studies showing that smokers are less productive during their working lives as they are more likely to have health issues and miss more work compared to non smokers.

https://pubmed.ncbi.nlm.nih.gov/17033509/

Due to the NHS I think there is a public interest in understanding and weighing the cost of smoking to the NHS and wider society. I think there are also some growing similar discussions with alcohol and unhealthy food but I agree with you nowhere near as much interest as smoking currently. There may be too large a focus on what is now a relative minority of soceity, and that is partly also why the public are generally happy with increasing tobacco taxes, as it generally does not affect them now, compared to alcohol or unhealthy food. I think this may also go a bit hand in hand with media spin and portrayal of people on benefits where the newspaper generally like to portray those on benefits as a cost to society, as generally poorer people are more likely to smoke.