Opensource

Yes they are unprivileged, and the gmscompat tool doesnt give them more access that is true. Still it is google software with the intention to control your device and spy on you, while Aurorastore is a slim app that even allows to restrict the apps it tells to Google.

If you're hiding system services in Aurora that you don't want it touching, that makes it even easier to identify you, because Google play doesn't do that.

It is less data. GrapheneOS will have less system apps than stock android so that immediately gives it away.

Asking Google for updates is also different from telling it a complete list of your installed apps. You might simply not try to update these system apps currently.

In the end, it is really good that play services work on GrapheneOS, but they are still more invasive as regular user apps than alternatives.