Spotify doesn't offer an API to allow me to replace their payment system with mine where I would direct 100% of profits to artists. Because that is their revenue source.
Is that better?
I will never use a purchase method on iOS that isn't IAP. Never, and I'm not alone.
Yes, it's dumb that they're not allowed to link to the website for people to purchase directly. I would prefer that they handle it like "login with Apple," where you can support others, but must support Apple alongside. I would always choose IAP, others could click and go through the extra steps to buy directly from Spotify. But it also isn't that hard to deal with. Amazon does it for ebooks, and people still buy ebooks from Amazon by going to the website.
Spotify is throwing a fit because they don't want to even allow IAP. They want the advantages of being on iOS with zero consideration of Apple or iOS users. Apple is going too far, but if I have to choose, I side with Apple here, because Spotify is throwing a dishonest tantrum.
When apps use IAP it’s very user-friendly. People sometimes prefer it over putting down their payment details in yet another app. I disagree that forcing apps to use IAP is user-hostile. I am not arguing that the IAP mandate is perfect, but these are the rules right now. And you can’t break rules just because you think they’re insane. Dura lex sed lex.
I think the point is that the rules are anti-competitive, user-hostile, extractive.