Notarization is also optional, annoying as a user, sure, but still optional

What would that difference be?

The “human review” part.

The fact that notarization is not required to install an app on MacOS.

I'm actually curious whether they're going to allow non-notarization apps to be installed, but keeping it hidden away.

But any developer distributing non-approved applications won't ever be allowed to distribute on the app store as well without paying those fees.