First of all anders you are not a very well liked person(see ban thread history) so you trying to recruit someone to fight in a battle doesn't carry very much weight in my mind.
Second of all its much easier to just move your pixel around on the strat map as opposed to showing up to a battle. Sure, if I'm around and want to do a fight and can dedicate what could take anywhere from 3-90 minutes I can do strat. I can move my strat guy while I'm teaching, coaching or cooking a family dinner.
Edit: you are right though, it does show max merc pool in theory.