^Depends on the image. Better than no reaction at all, and I've long since given up on trying to come up with a unique comment for every image, there's way too many of them to do so.
It's the artist's fetish. Their Pixiv is full of overalls and jumpsuits, usually with Touhou characters, and sometimes with some futa action. Pretty nice if you're into overalls (I am!)
It's the Kinokuniya USA store exclusive cover for vol 1. They teamed up with Yen Press for it. The other booksellers will just get the regular cover for vol 1.