[Merit Points] contained many uses within the Shiroichi School. Most notably, as a form of currency for, among other things, acquiring school supplies at the digital kiosks located throughout the campus. And, because a student's position on the leaderboard was calculated based on the total—rather than the current—sum of merit points they'd accrued, it didn't harm them in that regard.
Speaking of, Keiko could really go for a cool new eraser right about now, since her previous one had worn out.
"Remember your youth!" the disembodied head of a cartoon tanuki cheerfully greeted her, just as soon as she activated the kiosk screen, by sliding her [Shiroichi Watch] over a round, glowing red sensor located at the center of the large keypad. "Always remember"—it paused, its voice becoming stiff and robotic, like text-to-speech: "Keiko Nakamura"—pausing again, its voice then reverting to normal: "so long as you do as you're told, you'll be a popular girl that everyone loves!"