Yeah, this isn't really about "choice", it's about control. If there are exclusives on, for example, an iOS Epic store, your choice isn't really a choice, you have to install it from the Epic store.

I'm curious how this will play out in general. Android already allows side-loaded applications, and Epic allowed people to install Fortnite outside of the Play Store and it did poorly, so they begrudgingly added Fortnite back into the Play Store, so I imagine it would be the same thing on iOS. Arguably it could be even more challenging for others because Apple would likely not be forced to treat non-App Store stores the same as the App Store in some ways, which would very likely lead to a situation where users would get popups when when install the new app store and when they load an app, similar to how running a nonsigned program works on Mac now.