I love that Epic is doing this as it could finally drive the regulatory question of whether Apple's app store is a monopoly requiring intervention.
I'm not even sure I know exactly where I come down on the issue as I can see reasonable arguments on both sides. But I do think it deserves being tested.
(Note: obviously it IS a monopoly and does have huge negative effects. The question is whether the courts will find that it technically violates specific anti-trust definitions sufficiently to be successfully prosecuted.