> although at 15%, it's half the normal 30% rate for the app store
15% is the normal rate for the App Store. Only developers earning above $1MM/yr through the App Store have to pay 30%, the vast majority of developers only pay 15%.
It's not "normal", you have to "apply" (and get auto-accepted) but won't get the rate if you don't know to do that. You'll also get permanently booted from it if you do some things like transfer ownership of an account (if you want to sell an app you made, IIRC you lose access to this program, even if the app makes under a million).
15% is the normal rate for the App Store. Only developers earning above $1MM/yr through the App Store have to pay 30%, the vast majority of developers only pay 15%.