The scalability argument does not fly with me. Realtime Database is not scalable, and you will eventually need to use sharding to get it to work with reasonable

The scalability argument does not fly with me. Realtime Database is not scalable, and you will eventually need to use sharding to get it to work with reasonable amounts of data. Cloud Firestore is designed to extract as much money from you based on the structure of their pricing model - you are compelled to make unnecessary reads and duplicated writes in order to make comparable operations. If you want a scalable Nosql, why wouldn't you go for something like mongoDB cloud, which is far less likely to burn your startup's pockets? The most definitive use case for Firebase is its Realtime capability, which makes it useful for gaming particularly but also team-based apps. But Supabase is just getting started with their Realtime capability - I expect to see more progress from them while Firebase deteriorates under the cloud of Google (pun intended).