But the argument that allowing, or even encouraging, smokers to kill themselves and their other victims is 'beneficial' in a socio-economic context, and therefore justifiable, is morally bankrupt and completely unconscionable in 21st-Century civilised society (IMHO, of course - YMMV).

Yet that is what the Government are doing with drinkers .....
Ban alcohol and the incidence of liver disease would plummet.
or
Ban underage sex and there would be an immediate drop in deaths from cervical cancer.
or
Ban cars and road deaths would be non existant,
Allow people to live for ever and society would collapse

All I'm saying is look at things in the longer term and they have very different outcomes.