I like Apple's payment system. It works, it's consistent, I can cancel things from a single menu. There are real benefits to me, the consumer, to using Apple's system.
On the flip side, other payment systems can be a hodgepodge of unsecured, user hostile (cancellations), and inconsistent. There can be real negatives to using other systems. More so some systems that don't have a consistent UX (ie, don't bump me into PayPal's UX or similar and have a branded payment page instead).
Basically, I'm not a fan of Apple being this heavy-handed. There has to be a happy middle ground. But, I also hate inconsistent payment workflows and loathe cancelling subscriptions elsewhere. Not sure what the right answer is, but as a consumer, I'm finding it hard to care about this.