For me, though, some amount of harm is built-in to our condition.
We will eat junk sometimes, we will be sedentary sometimes- we might even overindulge sometimes.
For me, marijuana is recreational, like alcohol.
If a recreational session of marijuana is better for humans than a recreational session of alcohol, then I would actively promote that- since we are all keenly aware of how prohibiting all recreational unhealthy things goes in reality. “Perfect is the enemy of good”, in this case I might say that “perfect is the enemy of improvement”; maybe theres a better quote for exactly this.
Knowing that its better on your lungs than smoking, which was socially acceptable 20 years ago, goes a long way to helping.
Though I also agree with other commenters, its a low bar and the frequency of recreational drug use vs casual smoking is an apples to oranges comparison
It's bad practice to equate an offensive order with drug consumption.
(However in my adopted home we don't have public pensions like that. Your pension pot is yours, and if you keel over, your heirs get it. But smokers are still fiscally positive.
I brought up the NHS as a short-hand for any kind of healthcare system where the general taxpayer foots your medical bill.)