I never came across a rule that you can't use a source if its title and main point isn't reflected in the edit. That would be very limiting. However, this is not to say that the material I added does not reflect these. The authors discussion on the counteractive effects of cannabis is a major point. Regardless, what matters is that the details are relevant even if it doesn't summarize the source, the only problem is that if they contradict the source. Anyway, since similar details are in the article, I don't dispute the deletion. However, I would suggest that you define what you mean by beneficial to some users. It does not seem to be very informative.