Repertoir of Myriad Melodies

So I just finished the event thing and I can't understand why devs didn't offer better rewards for this feature. They obviously spend a lot of time and effort developing it, but if you're anything like me you played it until you got the rewards and never touched it again. It's fun, but that's about it.

I feel like they could have at least made the instruments available for these coins, because there's no way I'm gonna spend 150k mora for a guitar at the gift shop. They could have made some music-themed furniture or blueprints for the teapot, or even just some basic skill books and character/weapon mats. But there's no real incentive to use this feature unless you really like rhythm games and there are plenty of those out there already.