This is not nonsense.
GrapheneOS allows to use play services, without them having system privileges: Features overview | GrapheneOS
Advantages without the disadvantages. With play services, you can install and use play store.
You can use an alternative store you want, like aurora store, which doesn’t require to install the play services.
But if you need the play services, you might as well use the google playstore.
Everyone has different needs for their use, and a different security model.
Many use sandboxed play services, because it’s easy to install, offers great compatibility, and still limits the data that Google can extract.
You can even create a second profil and use play services only on it, completly separate from your main profil.
We do typically recommend Aurora Store even when using Sandboxed Google Play Services, because Play Services (like notifications, etc.) will still work without signing in to a Google account, but the Play Store itself does not.
But if you’re also fine with having things tied to a Google account then the Google Play Store works fine on GrapheneOS, yes.
Personally, I prefer to avoid intermediaries.
I understand that some may prefer the aurora store, even with the play services, but it’s still possible to create a google account, without putting personal information.