From what I read, people don’t chainsmoke blunts like they chainsmoke tobacco. Nicotine is much more addicting. Maybe some members here know better than me and correct me if my metzius is off.
There are perfectly legal “natural” drugs that provide a potent and dangerous high. these may be legal but the fact that there seem to be many deaths connected with them make them much worse halachicly than marijuana.
To be clear, I’m not advocating smoking marijuana. The psychological effect of doing something illegal cannot be underestimated. But if it was legal, halachicly it would be better than addictive smoking.