Today's the day.

Idk, it kind of makes sense to me. You participate in events, and play games to earn cash prizes!
Earning it via actual game-play seemed fine too, though it's one of those things that was easier for high levels that have lots of bossing options, since low levels would still be figuring everything out. Pretty much anybody of any level can participate in mini-games~

Man, I wish GMS would use the Mileage thing =[ it would help so much with how crappy not playing with NX feels.

That's a valid point, but why not just add mileage to minigames instead of removing it from actual gameplay? Now players have to waste time with a bunch of shitty minigames instead of just playing the main game and earning points. It's a really odd decision and I hope they don't implement it this way if GMS gets mileage by some chance.