I think there's something that can be learned from witnessing excellence in any area - writing, coding, music, sports...seeing the processes, discipline, out-of-the-box thinking, teamwork, etc. that lead to a great outcome can transfer over into other fields. Yes, sports are mainly for entertainment (and a series of never-ending cliches) but are also a microcosm of life.

That being said, I agree that you'll learn much more from reading books, taking a course, etc. than sitting down and watching sports for the equivalent amount of time.