A one day 10% off sale is a change in behavior due to no action taken by the user triggered remotely by the developer. Is a sale very close to malware?
Does the sale require me to submit payment details to a not-already-trusted platform?
The change remotely triggered by Epic redirects users to a third-party (Epic) payment system, but what if it were, say, a malicious Epic insider? How much user payment info/cash could they grab before they were detected and disabled?
They actually gave 2 options. If you didnt trust the game maker and their discount you could continue paying the premium to Apple directly and continue feeling safe.
It's funny that this choice wasn't "offered" to console users who got the 20% discount even as 30% still went to Sony/Microsoft. The two-tier pricing on iOS was purely a stunt and had nothing to do with Epic's costs.