I work for a company that enable people to record sports using video and the storage footprint are often very huge (10GB+). While building an app for iOS, I notice that Firebase don't support continuing uploads across process restarts on iOS which is a major deal-breaker for continuing using Cloud Storage for Firebase.
I see support for this on Android and I will encourage you to add this to iOS in the future. Ref: https://firebase.google.com/docs/storage/android/upload-files#continuing_uploads_across_process_restarts