To me, some of what makes game planning matter is just simple football logic - I still see a surprising number of coaches who will run on too often on 3rd & long. I get that running on 3rd & long can be a viable strategy *some* of the time, but not most of the time. And in real life it's usually in the form of a draw play, which I don't think you can really replicate via GD.
So it's good to use game planning to implement basic gridiron smarts at least, and avoid running for 4 yards on a 3rd & 9 play.