All the people defending Apple baffle me. Apple does not have your best interests at heart. They care about one thing and one thing only: profits.
That's said, I'm torn on this. I don't see why apps can't have links to their websites directing them to sign up. I find it annoying that I can't buy music downloads in Amazon's mobile app, yet I can on amazon.com in mobile Safari. It's clunky. Just allow developers more freedom with their apps.
Then again, Apple does deserve some sort of cut to reimburse them for their app and music store infrastructure.
But seriously, people, stop defending every single marketing and financial decision Apple makes. 16 gb of storage IS NOT ENOUGH. 1 gb RAM IS NOT ENOUGH. And yes, some of the policies Apple has in place, MAY just be considered anticompetitive.
Edit: 5 gb of cloud storage is pathetic. I have an iPhone 6 and iPad mini 3, and I can't back them both up to iCloud because their backups alone are more than 5 gb. How am I rewarded for my brand loyalty and buyin multiple Apple devices? I'll have to pay for more iCloud storage when someone who only buys one Apple device won't need to. Yet. Screw that. I started backing up both devices to my MacBook Pro again and haven't looked back.