There is. By only allowing purchases by in app purchases, Apple can force the app developers to be fair in their return/refund processes. There are tons of scum

There is. By only allowing purchases by in app purchases, Apple can force the app developers to be fair in their return/refund processes. There are tons of scummy companies and developers want to take money from the customer and not return it if the customer is unhappy or even when they are exercising their legal rights and hope the customers to not bother for their 1 to 5$ purchase. Believe me, the rules do make sense.