Not quite true. It will hook up any strategic resource but not any of the luxury ones. So when it comes to mining, it won't help with Gold, Silver, Gems, Salt, or Copper. But go ahead and plant it on Iron, Coal, Aluminum, and Uranium (or Horses and Oil).
Uh, are you quoting the right post?
I thought alL GP tile improvements connect luxury resources? I know for a fact that the great prophet does.