You are forced to use Apple for payments. It's entirely stupid to say "well you don't have to let users pay in the app". Every single user expects to be able to pay by credit card on their phone - the phone is a bloody computer. Imagine if your desktop PC only allowed payments via a Microsoft service that charged the application developer 30%. This would NEVER happen, as the very concept is absolutely ridiculous.

There is no technical reason to not allow an app developer to use an alternative like Stripe as their payment processor. Apple tries to sugarcoat it by using phrases like "seamless integration" for end users, never having to enter their credit card number. The reality is, it has nothing to do with user experience. It is 100% about getting that 30%. Nothing else.

I accept a certain level of a walled garden by buying into the Apple ecosystem. I absolutely do not condone charging developers 30% for payment processing. I buy apps from the store, and developers get shafted just for that. I have never, and will never, perform an in-app purchase without first checking whether I can pay the company directly. I don't care if it's $9.99 in-app, and $9.99 on an external web site. I will ensure that I pay outside the app whenever possible. The problem is that the majority of users do not do this. And they shouldn't have to.

It really hurts the user experience sometimes. Kindle books are an example I hit a lot. Amazon can't do purchases in the app without using Apple's in-app purchase system, which would likely cause Amazon to sell at a loss. They also can't even link to their web site, which of course still allows payments even on the phone. So if I want to buy a book, I have to manually go out of the Kindle app, into Safari, go to Amazon, find the book I'm interested in, purchase it, then go back to the Kindle app and hope it synced. If Apple would be less idiotic here, I could be done with one touch.

And of course Apple has iBooks and doesn't have to worry about losing money on each sale because of a 30% transaction fee.