For the same reason they’ve pushed Epic Games Store on PC - they take 5% of gross revenue as royalties for any product that uses UE4 and lower fees charged by distribution channels makes that easier to swallow for both larger and smaller studios.

Mind you, this is pure speculation on my part - but given they consider that 5% royalty paid as part of the fee for every title sold on EGS it seems likely that their goal is to sell more licenses, not just to cash in on Fortnite.

There are other App/Game stores. I think this is the first, but XBox/PS maybe in the future.

I wonder what percentage play exclusively on iOS though. If big spenders will spend on whatever is convenient it could be easily worth it to stop them from spending on iOS and get the cut back.

To serve as a warning to others