There was a post somewhere that I saw some time ago and there was a bathroom a lot like this, not all glass, but a glass window you could see to and from the bed, as well as mirrors all over that let you see to and from the bed and someone explained that those kinds of bathrooms/hotel rooms are that way for sex stuff, like paid sex stuff. I don't remember the exact reasoning, but it's not to watch someone take a dump. I mean I guess if someone's into that then two birds with one stone, but it was more along the lines of security or something, so you can see neither party is doing something malicious, stealing or spicing a drink with something.
Maybe this is something like that as well.