If the default apps are restored after a factory reset then "deleting" a built-in app in iOS isn't really any different from disabling an Android system app.
It reads just like the android way of disabling: Removes cache and user data, if you go to the app-store to 'enable' it again it has a small install file already on system and either automatically updates before use (iOS) or puts available updates in the download queue (android).
What happens if you resell an iPhone from which you've "deleted" apps such as Contacts, Maps, and Music? Does wiping and resetting the device restore it to stock condition, including those default apps?
If not, that seems potentially confusing for secondhand users. Some apps such as Phone and Photos cannot be removed in any way, but users may still be confused if other default apps are missing.