The new Google Play App Signing feature makes our apps more secure. If you opt in to this, it means each of your apps have their own individual signature.
I often forget to load that sig into the IDE and when I try to upload, the app is rejected. It simply means I have to recompile with that sig and upload again.
It would be very convenient if when loading an app, the IDE loads a default sig if one is found in the project directory.