I think you have to specify the use case.

I have an app that I built which has a couple hundred users. I pay just a couple dollars per month to use firebase firestore, authentication, cloud functions, storage, analytics, and crashlytics.

I’m sure thin.dev is very cool and I’m excited to check it out but I expect in the distribution of possible use cases, thin pricing is cheaper than firestore or real-time database in a vanishingly small number of them.