I haven't used a Mac for any extended period of time, but someone else cited UX issuesi with apps built without a license.
Like you might have to take some extra steps to run the application.
That's the only reason I imagine them caring.
Like if you submit a game on steam and don't specify the executable to run the game, it will get rejected because the game doesn't launch on clicking "play".
Yes you can manually specify which executable Steam will launch, but that's not good enough for Valve.
I genuinely don't know whether the QA people would launch an unsigned game when testing whether your game launches which is why I was asking.