Very much this. If you're looking at it from a pure productivity standpoint and want to try it out, and aren't a regular toker - don't - because you'll just get really baked. :P
Of course you're right - but drugs usually do deliver the benefits espoused (if often at a Faustian price). Your two statements are a shade oxymoronic.
Addictive habits form suddenly, but not immediately. Every drug requires a period of optional, regular, and increasing use before dependency develops. (Some, like nicotine, can have rapid dependency onset. Others take 6 or more months of intermittent use before withdrawal threatens).
This non-dependent yet regular use is usually driven by genuine (subjective) benefit to the user - euphoria or focus, amnesia or nescience, etc.
This is the essence of the word "drug": if inactive we say supplement, snake oil, homeopathic, etc.
Pharmacology _is_ somewhat magic - absurdly improbable in a way reality, and human endeavor, often is (see: organ transplants, the bioengineered mutant grass known as maize/corn).