Drugs like ibogaine in particular, and LSD and psilocybin to a lesser degree, on the other hand, have shown great efficacy in helping people overcome addictions. So by greater access to psychedelic therapy we could massively reduce the impact of the drugs that are causing harm.
Furthermore, it is very difficult to overdose on most psyechedelics as most people don't want to trip again right away after an experience, and also that the amount you need for an experience is often orders of magnitude lower than the dangerous amount (for instance you can have a significant trip on 100 micrograms of LSD, an overwhelming experience on 300 micrograms, but it would take many grams to be fatal).