I mean makes sense, we already know what Makoto is capable of, but we watch from the PoV of someone who knew he was a slacker in the real world and also knew he was the weakest in this world, also she didn't get along with him like Sa-san, so she probably wouldn't know he's very smart. And on top of that she told she has never seen a Spirit user so far, so Makoto could very easily be a sham.