Even when active, it didn't seem to really work.
So far as I could tell, it worked pretty much as intended.
But it would never be much help to a city. There just isn't that much food available there, ever.
That said, I have been pondering on how we could help keep cities from starving quite so often. I'm hoping that the changes to the food system we're making will help, but if they're not enough, I may try and come up with something else. Not sure what yet; everything I've come up with so far works with rurals, but not cities