I think Lumifer is suggesting that a model can correspond accurately to reality (e.g., representing the fact that X is in a hot air balloon 30 feet above Y's current location) but none the less be useless (e.g., because all X wants to know is how to get to Vladivostok, and knowing he's in a balloon 30 feet above Y doesn't help with that). And that this is an example of how a model can be "bad" other than inaccurate correspondence with reality, which is what you were asking for a few comments upthread.