What happens if you get 999 moons in Mario Odyssey?

I'm curious, could you explain to me what would occur in the game Mario Odyssey if a player were to acquire 999 moons? Would this achievement unlock any special bonuses, power-ups, or even hidden levels? Additionally, would reaching this milestone grant the player any form of recognition or bragging rights within the gaming community? I'm eager to learn more about the significance of collecting such a large number of moons in this popular Nintendo Switch title.