Do you remember the old days, when desktop apps (many written in Delphi) connected directly to the SGDB, relying on views and stored procedures? This kind of "server-client" software is still very common inside corporate LANs. Since the browser speaks a very limited set of protocols, projects like postgREST are just a bridge between frontend and storage, thus moving all needed business logic inside into the SGDB. This kind of model is hell. It's history repeating itself all over again.