Sure, just look at the positive pressure I mentioned in the end of my post. If we took all the money spent in the police, courts, & prisons for non-violent drug use offenses, and funded totally free to use, no questions asked, walk-in rehab programs, I think that would be both a massive financial and massive cultural benefit. Throw in awareness programs, counseling, poverty-area involvement, etc, and you'd still be way in the black.

Regulating substances for purchase by minors is something that's well understood and much more agreeable. Getting it into stores and away from pushers (which can still be criminalized, just not the users) makes it much more manageable for the problem cases, and much more available for any beneficial cases (self-medication, etc).

Characterizing that everybody's going to start using hard drugs if they're decriminalized is really kind of jumping off the handle, too. People have few barriers to hard drug access as it is, where this problem affects us the most. Many value their mental & financial state and have seen too many negative examples already and abstain, even if they're a classified high-risk sort of person. Others use whatever they can get a hold of, and legislation is irrelevant to their use. Yet others dabble or use sparingly, like your bad trip example. It's a personal choice, not a legal one, that's already been made millions of times over.

Besides, consuming junk food, watching TV, internet use, etc, have none of these usage laws while having addictive and society-wide negative effects, too. The question remains why other behaviors "must" be regulated while these aren't.