What is significant I leper's change of heart toward the war?

Leper is interested in bugs, nature, and not necessarily being involved in Blitzball, except on the sidelines. He's a typical weakling or even a nerd. He seems to be anything but army-ready.

Leper changes his heart when he watched the ski troops video the army recruiter presented. This is significant because it demonstrates the power of persuasion. He chose the army naively because he thought it was going to be fun. War isn't fun. It also demonstrated that the students who generally lead or make the first attempts (Finny or Brinker) in this case didn't.