See the other comments. The point is not a specific new interface, but a separation of concerns, and leveling the playing field.

I'll try to do an example. The kernel doesn't currently know about SQL. Instead, you e.g. connect to a socket, and start talking to postgres. Imagine if FS stuff was the same thing: you connect to a socket, and then issue various command to read and write files. Ignore perf for a moment, it works right?

Now, one counter-argument might be "hold up, what is this socket you need to connect to, isn't that part of a file system? Is there now an all-userspace inner filesystem, still kernel-supported 'meta filesystem'?" Well, the answer to that is maybe the Unix idea of making communication channels like pipes and (to a lesser extent) sockets, was a bad idea. Or rather, there may be nothing wrong with saying a directory can have a child which may be such a communication channel, but there is a problem with saying that every such communication channel should live inside some directory.