Well, I happen to like that any service I subscribe to using my phone can be unsubscribed in one click, without jumping backwards through hoops while standing on my head begging customer service to cancel and no I don't want to extend my trial at a special discounted rate. And the iPhone market is big enough that companies have to offer signup in their app. But if companies start drifting to only offering services via other stores or payments, then they will inevitably fuck up the cancel option again, and I will lose something.