The evolutionary advantage of it is fairly apparent - but understanding how we can control our own body chemistry without pharmaceutical intervention is of great interest to me.
It's a silly example but what if you could combat age onset testosterone decline with brain exercises or by watching an hour of UFC everyday. I'd take that in a heartbeat over hormone therapy if it worked
I have no clue how that mechanism migh operate, of course. I realize that makes this comment less persuasive, but so be it.