No. Criminalization does more harm than benefit.
For the vast majority of drug users that are not addicted, this is obvious.
And for the addicts, criminalization is the last thing they need. Deterrence might prevent a few people from getting addicted, but not many. A lot of drug addiction is downstream of homelessness and mental health issues meaning the illegality is a very weak deterrent for the most vulnerable.
If we pushed even half of the money spent policing the war on drugs into homelessness support, mental health services, and addiction counseling and harm minimization like needle exchanges, we’d see a huge reduction in harm.
The current regime is not really interested in harm reduction; there is no effort to compare interventions based on objective harm metrics. Instead non-harm metrics like arrest rates and usage are chased. The policies start from Puritanism and historical racism and justify themselves claiming to care about harm after the fact.
To your second point… I think the racial discrimination baked into the history of drug enforcement should steer us away from giving police more excuses to incarcerate on their discretion. But even ignoring that, I don’t think we should support “we knew but could not provide evidence to prove guilt”, the justice system requires evidence for a reason.