According to App Store rules, if an in-app payment all goes to the creator with zero platform cut, then Apple foregoes the 30% fee.
> On Android, tips can also be sent within Spaces.
Then why they couldn't do this on iOS as well?
3.2.1.vii Apps may enable individual users to give a monetary gift to another individual without using in-app purchase, provided that (a) the gift is a completely optional choice by the giver, and (b) 100% of the funds go to the receiver of the gift. However, a gift that is connected to or associated at any point in time with receiving digital content or services must use in-app purchase.
Since Twitter's cut is zero, they owe Apple 30% of zero.