In the UNIX world, that's what it gives you - a stream of bytes. Hence things like rsync-over-ssh or git-over-ssh. It also has a port forwarding mode which has special support for X11, which gives you remote windowing over a stream of bytes too.
The main, huge, benefit is that the abstraction is pretty simple, it's discoverable, and you can use the same interface as a human. You can also plug any stream-of-bytes into any other stream-of-bytes, whereas API or RPC based systems have to be designed to interoperate.