There are many other members of the Aimeetaf outside of Evey and Cecile. They come from all sorts of different places and each has their own way of dealing with things. 

Take for instance Shob Meenown of the planet Regesir. His gedutu took the form of a rock. He didn't use it to summon anything except other bigger rocks. Not even different kinds of rocks. It was always the same nondescript solid rock. I don't even think it's fair to say he liked rocks. He liked a rock and kept making that rock.

You'd think that make him completely useless but he's been able to settle into a groove where that works for him. Collapsing structure? Hold it up with a giant rock? Bomb? Cut its power supply with a tiny rock. Get in a fight? Well, that one's pretty obvious. There are many uses for rocks and he's found a lot of them. 

One could say he's just been incredibly lucky and one day that luck will run out. Or he could have completely figured out the one thing he's good at and is using it to his full advantage. I'll let you decide.