We have developed several applications that transfer users to the portal for paying for web pages contained in the application.
Apple proved to be excellent with this approach, in one specific application we implemented both an In-App purchase and a user payment portal - they asked us to remove the In-App purchase, because the application sold the transaction / vouchers, and they classified it as a virtual product. .. they denied nothing in our user payment portal.
Potentially, they could pull out all the applications that do this at any time they want, although I do not see a likely scenario in this.
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