Tolkien Enterprises have non-literary uses of "hobbit" nailed down by Hollywood lawyers bearing trademarks. Note that the outfit has nothing to do with the Tolkien Family, and hold the movie rights. They licensed both the Bakshi animation and Peter Jackson's version. In British law, at least, "hobbit" may not be quite so secure as a trademark, as I know that Tolkien Enterprises were using "hobbite", and PBI Cambridge had a trademark on a wheat variety called "Maris Hobbit".