Unless you are writing an app that should also work offline. In this case, most of your logic _must_ be your frontend, and your backend is mostly a data reposit

Unless you are writing an app that should also work offline. In this case, most of your logic _must_ be your frontend, and your backend is mostly a data repository for data backup and synchronization. In such a scenario, database-as-an-API seems to be exactly the right approach.