I first got the Kamaboko with no accessories but after a couple uses, I wanted an add on. I got the zashiki first. I haven't used this except a couple times when it was raining when I camped. Pretty rad watching a movie while it's raining outside. I guarantee we had a better time than anyone else at the camp site!
I've never seen a theater attachment to a tent. We used it one night but as expected after a long day, the kids were asleep within 10 mins!