Aren't you guys old enough to behave as adults? What can you possibly gain from fighting whoever besides betting is envolved?
Humiliating the loser. Teaching one to think twice before opening his big mouth. Learning to be humble and respectful.
A lot can be gained by a good, old fashion ass-kicking. That applies whether it's between two individuals or even two nations.
When all is said and done, individuals, and the world, are still ruled by force.