Bidets have never caught on in the United States, perceived as a fixture meant for posh hotels an prissy home bathrooms. Of course they're quite the norm in Europe, Japan, and other regions. But not only are bidets more sanitary than toilet paper, they're actually much more eco-conscious. From Scientific American: Justin Thomas, editor of the website metaefficient.com, considers bidets to be “a key green technology” because they eliminate the use of toilet paper.