The wiki is quite unclear on the Champion. From what I gather he might "boost the morale". Is there a point to appointing one?
The champion is a noble position appointed by the Baron (that is, you can appoint it, but you can't do so without a baron or greater noble being present). A champion has no special room requirements, but may make a single demand eventually. As the title of champion is bestowed by appointment rather than merit, you may want to have your best teacher be the champion and conduct weapon demonstrations to boost the morale of training soldiers while your toughest killers go out and fight goblins.