This house is really amazing, but this bathroom is a little much: https://www.oldhousedreams.com/2012/03/29/1960-lambertville-nj/ (Last sold in 2015 for $630K: https://www.longandfoster.com/homes-for-sale/315-Goat-Hill-Road-Lambertville-NJ-08530-250220020)
I’ve seen this before…its a wet bathroom, which means it’s water sealed with sealed electrical outlets and extra drainage. You can take a hose to the entire bathroom to clean it. That’s why there’s no shower curtain, since it isn’t needed. It’s kinda overboard, but people with money seem to like them.
I don’t really see it as overboard. People in Japan (and elsewhere) have wet rooms. I’m a fan of them, cleaning is easier and additional protection from flooding. It’s the exact opposite of carpet in the bathroom.