Out of curiosity, I stayed at a capsule hotel in Japan once, and their "pods" seem about equivalent in size to a coffin apartment, at least the ones I've seen in articles. To be honest, it wasn't nearly as bad as I expected; kind of cozy, though I still think it felt like the human equivalent of a kennel.

However, I'm also pretty petite, and I only stayed for one night. The idea of living in one is mind-breaking. You can't even stand up. I'm sure many people can't even sit up straight.