Too many of these companies have dark patterns for canceling your subscription (or hoping you forget you have one) that I actively stay away from most services that I can't just use an IAP with. This is largely thanks to all of this being consolidated in a single UI where with just a couple clicks (without ever needing to open the app and dealing with their marketing or 20 questions) I can cancel a subscription.
Apple will email me when a yearly subscription is about to bill, clearly telling me how I can manage or cancel it (again outside of the app).
I understand why businesses may not like this, but as a consumer I value this heavily (and yes I do find myself annoyed by what I often hear also being in the tech industry).
At the same time for individual digital purchases I don't want to give every company my credit card. I would much rather that go through Apple.
I understand the concern about the "30% cut" but I wish these companies would also realize that I (and I assume many others) spend more money though my phone because I can do it through Apple where otherwise you would not be getting my money in the first place. So its 70% or nothing from me. Especially when there are alternatives that will be more than happy to take that money from me.
That doesn't mean that I don't use my credit card in some places. But those are for physical items. Likely at stores that already have my credit card in the first place.
At the end of the day, it is Spotify that is choosing to make customers jump through hoops. They chose to enter this market knowing that this will be an issue (if they did not expect this issue... honestly fire whoever decided to go into this market).