Because Owl is not a battle morph? There are much better options, given all the possibilities.
It is all about diversity. Having only big and powerful morphs isn't always good.
What if you have to fight in darkness?
Owl's great senses do help, you could use it as scout morph and also capable of causing some damage(they are silent predators, after all)
While Tobias's hawk wasn't as big or powerful as the others. He was still damn good at stealth flying and clawing people's eyes out. Owl might work for that.
