It's true they can do some pretty incredible things with coinage. Unfortunately every little extra bumps the price on the card guard, may be best to keep it a little simple if offering one at all. I don't know though.
While I do like card guards, I never really see them as must haves. Of course, there are always exceptions but those are obvious. For the fish deck, I think a lure or fishing spoon or whatever it is they use on those catch whatsits on those big fish shows, kind of card guard would be cooler than the typical disc. A big fishing hook would be cool too haha.