Have you done the tutorial missions? If not, then you're missing out on bunch of free silver units for CCing or whatever other purpose. I say this because it looks like you don't have Katie. And Katie is a reward in there. You also get an Cloris if you like her.

Reasons is because Katie is a soldier that have highest defense out of all soldiers that I know of unless there's something on DMM Aigis with even higher defense than katie for a soldier.