Because there will be many applications you may need to use e.g. banking which will be on an alternative App Store purely so they can skirt Apple's privacy restrictions. Finance is one sector where they would love to siphon all of your user data in order to better promote products and reduce risk.
If the third party App Store is owned and operated by the bank then there would be no choice.
And given that the benefit of doing so is unlimited access to user data and the capabilities of the hardware then it would be hard for many companies to not consider it.
You can switch banks? Trust me if these banks are only following the rules because of Apple, I can guarantee you their backend is definitely not following these privacy rules.
Also, OS level permissions don’t need to go away for third party apps.
Why can't they? They control the objc runtime, and IIRC the way message passing works in that system requires throwing strings around with the involvement of the runtime.
This being entirely separate from using allowed APIs for unapproved reasons, after passing whatever review/scan is done.
Or not allow all apps to send messages to the objects that host those private APIs. Again, unless I don't understand how the message passing system works in objc/swift. (most of my knowledge of the internals comes from reading blogposts on nshipster.com years ago)
I am much more worried about Apple siphoning my data than my Credit Union. Apple is building an ad mega-empire, in big part via abuse of power on their monopolistic platform.
Because there will be many applications you may need to use e.g. banking which will be on an alternative App Store purely so they can skirt Apple's privacy restrictions. Finance is one sector where they would love to siphon all of your user data in order to better promote products and reduce risk.
And so I would be forced to use them.