My opinion is "your merits your rule" send whomever and wherever you want.
I tend to agree, though as a merit source I wouldn't merit any user as a form of saying thanks or showing appreciation or the like. IMO campaign managers getting merited in the campaign ANN threads is a poor use of merits, and I get the feeling that sometimes that's done with the hope that it'll increase a member's chances of getting accepted, but who knows.
Just give merits and as much to wherever you want mate.
Eh, within limits I'd say. There are definitely bad uses of the merit system, e.g., selling merits and helping friends/alts rank up regardless of post quality, but as long as there isn't blatant abuse going on you can do what you want with your own sMerits--including giving them to a bounty manager.
Edit:
You can use merits in whatever way you want, as long you're not abusing system by selling merits, giving to your alts or sth.
Doh! I just wrote almost exactly what you did, but I swear I didn't read your post first. That's a really bad habit of mine.