Earlier quoted context omitted.
The reason is that Apple specifically requires all digital only purchases to only use in-app payment and must give Apple 30%. You are not allowed to process digital purchases through an app with your own payment system. You also can’t tell people that or link them to the website. This does not apply to physical goods. Which is why all the apps you mentioned are fine. This is the same issue that has been talked about…
> The reason is that Apple specifically requires all digital only purchases to only use in-app payment and must give Apple 30%. You are not allowed to process digital purchases through an app with your own payment system. You also can’t tell people that or link them to the website. > This does not apply to physical goods. I don't really get this division other than "it's what Apple could get away with". As far as the…
The world we now live in is that all "apps and programs" can be either a one-off purchase like a physical good or a subscription. That subscription might be for the "app" or it may be packaged as a subscription to a "service" that the app is facilitating (the line between the two is very blurry). Additionally, all digital goods like books, music and movies may also be a one-off purchase or a "subscription" like audible, apple music, etc.
The line between all of those is blurry such that, any set of rules you write leaves it open to convert "app sales" to "services/subscriptions" or even to bundle access to your app or it's content as "digital goods" to avoid that 30% cut. People would (and do) switch their sales model to then avoid that cut.
I don't have a solution and I don't think Apple or the open webs way is specifically better in every aspect, but I do think it's interesting to think about the problem space.