To use one Zynga game as an example, it's great to get notifications from Words With Friends when it's my turn to play. The "you haven't played with <Facebook friend>! Start a game?" notifications, not so much.
Definitely makes sense for multi-player games. I had Draw Something sending me notifications for a brief time now that I think about it, until I got bored with it.
I guess that shows the importance of the policy in question, to provide an disincentive for companies to abuse the privilege. I'm not sure if that applies in this case however, when marketing-driven notifications are actually desired by the users.