You're incorrect -- this is an example of the rule, not an exception.
Apple will not let Fandango (or anyone) sell a real-world item through IAP. That is why PayPal is acceptable. It's clearly stated in the app guidelines that IAP must be for virtual / digital items only.
I worked on an app that let you buy drinks at bars. In-app purchase was clearly out, so we integrated PayPal and Stripe. Apple allowed that and it's been in the store, with periodic updates and their reviews, for years.
PayPal has obtained appropriate licenses to act as a money transmitter in most states [1].
I can't tell from a casual reading of Blockchain's site if they are doing anything that would require state licensing or not. It seems that they hold a backup copy of their user's Bitcoin wallet. If that is just a backup for the "real" wallet on the mobile devices, or just used for syncing copies of the wallet between the user's multiple devices, my current vague understanding of the rules is that this would not be money transmission. However, if their servers are acting as intermediaries between the user and third parties for the exchange of Bitcoin (for goods, services, or real or virtual currency), then I think that would make them a money transmitter (or even make them a bank, which also opens up a huge regulatory can of worms).
Apple will not let Fandango (or anyone) sell a real-world item through IAP. That is why PayPal is acceptable. It's clearly stated in the app guidelines that IAP must be for virtual / digital items only.
I worked on an app that let you buy drinks at bars. In-app purchase was clearly out, so we integrated PayPal and Stripe. Apple allowed that and it's been in the store, with periodic updates and their reviews, for years.