[Firebaser here] that’s not quite accurate. For cloud functions they’re literally the same. Your Firebase function is actually a GCP function that you can manage behind the scenes.

With Cloud Firestore (our serverless DB) that’s the case as well. And Firebase Auth can be seamlessly upgraded to Google Cloud Identity Platform with a click.

However you’re right that for many Firebase products (Real-time Database, Hosting) there’s no relation to Cloud Resources.