Even if you are a completionist like me, you shouldn't worry about this one. These are all 20 second clips uploaded to Twitter. There are no voices, 2-3 generic music tracks that are probably from the regular OST and just paint animation with moving mouths and speech bubbles. I'm not even sure why I watched all of these, since I don't speak Japanese anyway. If you can read the language, there might be a bit more enjoyment to be found here, but this is very simple promotional material and you are not missing out on a super secret Chuunibyou special by skipping it.