Of course your mouth may smell better, and your teeth may stay healthier for more years… However, you may not realize those things in short term. What you do realize and feel good about is that you are being obedient and making your parents happy. And you know that your parents told you to do it for your own good and that’s why you keep doing it.
So back to what Gavra_At_Work suggested ???? ?????, that it is a siman, not a ????. The very fact that g-d told you to do it is a proof, as it were, that it is a good idea, but not necessarily because He told you to do it. I don’t like that idea.
PAA – Well put. “Would you do it? Why?” is a much easier way of explaining the question than “Why should…”!
Avram – I didn’t have time to read through your post properly, so I won’t comment, but I can tell you that although PAA is an avid Harry Potter fan, he isn’t a Parselmouth!