"Where there's a KC, there's an engine" well, no. But you know, throw ANY cantrip in, even pearl diver...
But Marin is both bad (relatively anyway; he's much better than he used to be) at BM, and he absolutely hates it. He will go for an engine if remotely viable, and sometimes, you're surprised at how well he does. But strategically, he may figure he's worse than you at BM (I would), so he feels he has a better chance with an engine(?)