Legally, if you take a position in federal court on X (i.e., that it's okay to ban external transactions by apps using your app store), and you are found to be doing not-X in an analogous situation (i.e., setting up external transactions to avoid fees in your competitors' app store), the court can rule against you in the original case...and then sanction you and your lawyers for wasting the court's time proclaiming X...and then legally bar you from asserting X in those proceedings, or related proceedings.
Courts are generally okay with some form of alternative arguments, (i.e., I didn't do Y, but if I did Y it was legal for me to do so), but they absolutely will not accept contradictory arguments by the same party (It's okay for me to do Z but I won't allow others to do Z in the same situation).
Legally, if you take a position in federal court on X (i.e., that it's okay to ban external transactions by apps using your app store), and you are found to be doing not-X in an analogous situation (i.e., setting up external transactions to avoid fees in your competitors' app store), the court can rule against you in the original case...and then sanction you and your lawyers for wasting the court's time proclaiming X...and then legally bar you from asserting X in those proceedings, or related proceedings.
Courts are generally okay with some form of alternative arguments, (i.e., I didn't do Y, but if I did Y it was legal for me to do so), but they absolutely will not accept contradictory arguments by the same party (It's okay for me to do Z but I won't allow others to do Z in the same situation).