The gacha game mechanics of Infinity Nikki are a way for players try their luck at getting pieces of outfit sets by spending either resonite crystals or revelation crystals in a random pull from banners. The resonite crystals can be used on permanent banners, meaning that they are sets that are going to continue to be available for people to work on collecting. However, the revelation crystals are much more precious, working on the limited-time event banners which change regularly.

https://screenrant.com/infinity-nikki-limited-revelation-crystals-starwish-gift-event-resonance/