Seems like there are a lot of illegally kept animals here...

[adamjeffery]

Monetarily worthless? Weed is actually very valuable. There is a thriving market for buying and selling it.

Effectively worthless? Weed will definitely produce an effect. Its even legal in some states for medicinal purposes of which it has more than a few.

I am not sure on what other basis you could call weed worthless. If you are merely referring to the fact that its illegal for recreational use then why not just say that, although it would be stating the obvious.

worthless as a recreational drug...
tons of other uses if it was in fact legalized