Firestore clients: To cache, or not to cache? (or both?)

The Firestore client SDKs have this handy feature called offline persistence (currently for Android, iOS, and web only). It helps your app built with Firestore to be usable without an internet connection, as far as database access is concerned. From the documentation:

This feature caches a copy of the Cloud Firestore data that your app is actively using, so your app…