I'm on weasel's side, but I can understand Apple wanting to keep iOS trusted by its users by restricting unapproved software coded to their current native app A

I'm on weasel's side, but I can understand Apple wanting to keep iOS trusted by its users by restricting unapproved software coded to their current native app API layer. What I can't understand is the harm for end users in apps using 3rd party payment processing without giving Apple a cut. That restriction encourages a worse experience for users who now have to go to the vendor's website to complete a purchase they could be making in-app.