This is pretty much the definition of filler. I believe that the general explanation for this recap was just because there were 13 weeks in this cour where Youjo Senki had to run, so the studio used the opportunity to splice something together since they didn't have the budget, or enough story material, to make an actual episode of new content. I suppose that's better than a situation where they just ran behind schedule and had to scramble, but it's not much of an excuse even then. I like Youjo Senki a lot, but the story isn't all that complex, and the animation isn't thatamazing, that some kind of clip episode was warranted.

There's zero reason to waste your time on this.