The how matters because if you have a handle on the how you're not blundering around in the dark bumping into the things and thinking that waving a dead chicken around is what matters - when it could be something else that you haven't been paying attention to. (E.g. my experience of alternative things is that the efficacy is in the practitioner, not the technique.)

With all of these things you have to be sure there's a What before you start asking about the How. Acupuncture built up a fairly solid body of evidence for itself over a long time, and eventually the medical profession grudgingly started to take it seriously.

With something like moon lore, there are two problems. The first is that if you look at crime records, hospital admission records and other hard data there doesn't seem to be any real effect. This could be because studies have asked the wrong questions, but the current state of what's known isn't encouraging.

But assuming there's a real effect - my problem with a statement like 'It words on the tides, so of course it works on humans' is that it's a pseudo-how.

It's fine for people who want to believe it, but if you accept it it closes down further curiosity.

Once you believe you know what's happening, you lose interest in anything that might challenge that - and might also deepen your understanding beyond the usual received explanations.