I'm gonna keep this review pretty short since there is not much to say anyway. Every episode is the same, a diary entry on the right side that gets filled in as kaori talks about what happened, while the left side of the book shows some flashbacks of that scene. Therefore, there is no real story, since it's all flashbacks anyway. But then, why'd I give it 8/10? Well, if there's anything to be said about these specials, it feels like an amazing way of looking just a tiny bit deeper into the MC's thoughts, which I guess isn't really character development, but we do get toknow the MC's better, which I love.
The second reason is just the way it's built up. A single character, voicing the "thoughts" he/she has while writing them down, all the while a calm song is played in the background. It's perfect!

Also it's only like 15 minutes in total, if you're wasting your time watching anime anyway just watch it after you watched the main anime ok? :P

I guess it scores pretty low because it doesn't contribute to the story and is not in any way exciting, but its very heartwarming, and that for me has its own charmes