Compare this to a large application where you are marshalling objects from the HTTP POST request into temp objects inside your application language. Making that work with all clients, within all server contexts, is a lot of code which I hated to write.
With serverless, I'm never connecting my clients or backends directly. I'm thinking in terms of moving high level objects (JSON, files, events) between systems, and Google provides the glue to wire those together. It takes a mind shift, but when you realize how much glue code you are writing and that you can forget, it makes your application layer really simple.