Apple is giving you an out from customer service. If someone needs to unsubscribe or has issues with their subscription — it is no longer your problem, Apple needs to fix that.
While that can certainly be seen as a benefit for small iOS development shops or small publications it’s a dangerous risk for a business to take.
When users struggle with your payment gateway or feel that you’re unwilling to provide a refund or cancellation when things go wrong you are dead in the water. No money, no business.
iOS developers already give Apple control over a lot of the financial side of their business. Now Apple will control the downloading, billing, recurring subscription charges, and unsubscription process/support.
App developers will be passing more control over the revenue side of their businesses to Apple, who is probably not focused on crafting the same happy experiences for your paying users.