I just watched an episode of House Hunters featuring a couple named Seth and Keri looking for a home in Delray Beach, Florida. One of the featured houses had a glass-enclosed toilet in the master bath. I couldn’t tell for sure but it looked like there might have been no door to the bathroom, which if you like that kind of look, would have made good sense for there to be a separately enclosed room for the toilet. But this one was all glass. All glass. As in, sit on the toilet and look our at the world around you, and vice versa.
How very odd. I have not been able to find any references to why such a closet would exist. If you came here searching for the same answer, let me know if you found any updated information (or what your theories are!).