Official word: Gives teams a chance to see where they stand.
Real word: Gives media types some content.
What I don't like is how Alabama is the only team that consistently is given "the eye test" bump. They are unbeaten; but, the teams they have played have the worst winning % of any collective group of opponents by any Power 5 team. I guess they've "looked dominant" beating such a hapless bunch of teams, though.