Courage is one of the hallmarks of Gryffindor house, and it's also a defining characteristic for our main characters. Harry, Ron, Hermione, and even Neville all reveal themselves as possessing outstanding bravery, and it's their courage that helps them get through the climactic ordeals at the book's end. As Dumbledore praises them at the year-end banquet, he honors their explicit and implicit courage. This shows that the Hogwarts faculty values virtues like courage and loyalty as much as they do more wacky branches of magical education. Being able to make feathers float is all very well and good, but when push comes to shove, what really matters is how you face your fears.