You know, it's funny how straight-forward they are by saying "it's like checking ID at the airport." I think they want to make it impossible to create and distribute apps that they or their partners don't like, e.g. apps that circumvent Google ads or humanitarian resources that enrage not-so-humanitarian regimes. It also seems to be an attempt to circumvent right-to-repair by making it harder to root your phone or install custom ROMs which would give access back to your choice of third-party app host. I don't think it's truly about malware, because we already have third-party apps blocked by default. Android warns you it's an APK from an unknown source and it could hurt you, and makes you enable installing it, which is pretty hard to do accidentally.

That said, I think most emulators should be fine. Almost all of them use handwritten code and nothing proprietary. Google Play already hosts some. I assume most of those developers aren't gonna have a problem with package signing or authenticating themselves, because no one of consequence is going to have an objection with their work existing. Corporations lost the battle over emulators long ago.

I did disable Play Services out of principle though, because I completely agree it reeks of overreach. I don't use anything that relies on it anymore, and will be using alternative APK sources from now on. I paid for the phone, and shouldn't be able to do any less with it than I could when I bought it.