But how would you know that the special honey was something Souma specifically sought out, as opposed to having it lying around?
On the flip side, how did they know Hayama didn't actually think about all sorts of combinations before settling on "normal" spices being the most effective?
It relies on the story, rather than the taste. Also, a flaw here is that Hayama's dish could well have used special thyme etc - but no one else would know that because they don't have superhuman noses.