Was a recap necessary for 6 episodes?
At least the recap is well done, if you actually forget everything and don't want to watch the first half again, it's a good thing, and they cover basically everything important on that first half, it was even good to me, who watched the anime late at night and forgot a lot of stuff, so that's a good point.
But in general, it was actually really unnecessary for a 12 episodes anime, they could've made 13 episodes with more content.
Well, it's an average recap, you can skip it if you remember everything.