Again, the scaffolding effect. Greatly illustrated by how the civ games teach about history: they teach absolutely nothing, all their models are fantastically wrong and a core element is the counterfactual nature of how a game plays out (culminating in Gandhi's bomb threats). But they give mental scaffolding that is valuable in those topics where you'd otherwise start from an empty slate. When for example you know nothing about west African history and read a text about it for the first time, just having that image of the Mansa Musa avatar in your mind will give you a retention advantage over someone who doesn't have it. It works much like a condensation seed then, a mental bookmark to which new information can be attached before getting lost as essentially noise.

But I wonder if that might also come as a disadvantage in the classroom, where the remaining facts and methods grind has to be enforced: if, for some reason, you felt the need to make pupils knowledgeable in the sequence of popes, that incredibly boring class would naturally be spiced up with anecdotes of dual antipopes, the cadaver synod and so on. Would that last hope of making that class somewhat bearable be lost on someone who already knew those rare fun parts in between all the numbers, e.g. because of playing CK2?