Instant best up is right for pressing purchases, like restricted-time banners or in-sport movements in Wuthering Waves.

https://www.scribd.com/document/987792285/Wuwa-Top-Up-vs-In-App-Purchase-A-Complete-Lunite-Pricing-Guide-177725

Instant desirable up is right for urgent purchases, like limited-time banners or in-game routine in Wuthering Waves.