aniviakid

If you want your "app" to be in the "App Store", then you have to decide if you want the app to cost money (from which Apple will take a 15% or 30% cut) or if you want to make your money through a subscription process (or both, but that's redundant and greedy.) Apple will take a cut of your subscription if you include a button in your app to pay for the subscription through your app. However you can get your user to pay outside the app, in which case Apple takes no cut, but if you do that then you have to choose one of the following options:

1. You either include an optional way for the user to pay within the app, which will give Apple a 15% or 30% cut; or
2. You do not mention anywhere in your app that the user can pay for your services outside your app.

If you can't agree to either of these two conditions, your app violates the App Store Guidelines.

If I am wrong on anything, please explain why. I want to be corrected if I'm wrong. Who doesn't?

Option 1 is pretty close, and I'm sure devs would be fine if these were actually the two options. Option 1 is actually NOT optional -- Apple forces you to let people pay within the app.

The problem seems to be that if you let people buy things outside of the app that they can access in the app (eg a subscription or Fortnite VBucks), Apple forces you to let people buy them in the app as well (and pay the 15/30%).

SO if you sell VBucks outside of the app, you HAVE to sell VBucks in the app, using in-app-purchase and Apple gets their cut! Only streaming services are allowed to not offer IAP. Other developers are actually FORCED to use IAP and pay the 15/30% if they let users purchase those same things outside the app, AND they are not allowed to tell people that they can buy outside the app. 

If they weren't forced to let people buy stuff in the app with IAP, then that probably make a ton of devs happy. Similarly, if devs HAD to offer IAP but could tell people it's cheaper elsewhere, that would probably work too.