There are a few reasons people might put covers on toilet seats. One reason is for hygiene purposes. If someone is worried about germs, they may opt to use a seat cover so that they don't come into contact with any bacteria. Another reason could be for comfort. Some people find it more comfortable to sit on a softer surface, and a seat cover can provide that. Finally, some people just prefer the way it looks! A seat cover can add a bit of color or decoration to an otherwise plain bathroom fixture.