Apple draws a pretty clear line, it's the difference between buying a book and an ebook. An ebook is delivered and consumed on your iPhone or iPad, a book is not.
If Amazon, Uber and Lyft drop iPhone support, people will atop using iPhones and that's pretty much the only reason Apple doesn't charge them a commission.
Ever wonder what would happen to Uber and Lyft lost iPhone customers as a user base?
That could definitely put a hamper on new iPhone sales.
Meanwhile an app whose subscription model is “you get access to digital content” falls square within Apple’s IAP rules. I’m rather shocked Fanhouse got approved in the first place.