As a consumer there is definitely a tangible benefit to having the App Store be safe and consistent. Apple can impose its technical, moral, safety, and design philosophy on every app in its own stores like Disney or Whole Foods might with their retail products.
But if Hey Email or ClassPass or anyone else doesn't like Apples offerings, they can go to a 3rd party store and be available there. Like the new browser entitlement, Apple can choose which 3rd parties are able to allow installs (and hopefully some regulation prevents this from being anti-competitive).
There is no anti-competitive measures because there is no singular channel to install an app on an iphone anymore. And then Apple can make their App Store even more tightly controlled because every developer there is there by choice. Apple can cut custom deals to keep Google, Facebook or anyone else there, but Apple has to earn those partnerships like on the Mac App Store