Not good enough for a political party? The Greens have been in government in Germany, Finland, Norway, Iceland and a couple of other places that I can't remember off the top of my head. They've actually provided the foreign secretary in Germany. It suggest that they're a bit more than a pressure...
That's not a green policy though, that's something that's been made up.
I do agree though that the Greens have made a terrible choice as leader: wonder how much better they'd be doing if they still had Caroline Lucas (or had elected Peter Cranie)