Currently, you need to use Xcode or Cordova to sign an app for the iOS AppStore. For Android, it's a lot easier as you don't have to use Cocoon or other services to upload to GooglePlay.
Build in iOS export functionality so you can just upload to the AppStore with minimal tinkering.
The main problem with supporting an easier export to the iOS app store is that Apple impose very strict limitations on how iOS apps are published. For example using a Mac is mandatory, and very few hosting services provide support for Mac since Apple also ban using macOS on virtual machines. Additionally as it stands a Mac is still required for the final upload to the App Store. This means even if our iOS app export option did more for you, you'd still need to use a Mac for the final steps. In light of this, using an Xcode project is probably not significantly much more work than any further export option we could create - and creating such an option could involve several major difficulties and significant additional running costs. Therefore we don't intend to provide any further iOS export options at this time. We may revisit this in future, but the main factor is whether Apple will lift any of the restrictions that make supporting this so difficult.