Keep in mind Firebase has a big caveat. Firebase is great... for what it does. However, there's no way to easily migrate the Firebase resources to the larger GCP ecosystem. Firebase does what it does, and if you need anything else, you're out of luck.
Firebase is magic... but I never recommend it for anyone, until there's some sort of migration path.
[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.
Deploying is super slow. Usually it takes a minute or two, which is already quite long, but sometimes something goes wrong and then you can't redeploy immediately. You have to wait a couple of minutes before being able to redeploy.
To be fair, Firebase recently released a local development tool which alleviates the need to deploy on every change, but I haven't used it yet.
I'm a big Firebase user with Firestore and has been great...no not perfect and the "cold start" is probably the worst issue. However, deployments are easy, the GUI tool keeps getting better, like the extension packages, and the authentication system is quick to implement.
