They're not better than raw sockets, they're simply an abstraction layer on top of them.
For example, building a message queuing service using raw sockets that works on Windows, Mac OS, and Linux is quite the undertaking. With ZeroMQ (and I'm assuming nanomsg as well), it's quite simple.
This look cool! I have a small suggestion though. I think you should put an animated gif in the GitHub readme showing it in use. Maybe even use something like https://asciinema.org/.
For example, building a message queuing service using raw sockets that works on Windows, Mac OS, and Linux is quite the undertaking. With ZeroMQ (and I'm assuming nanomsg as well), it's quite simple.
ZeroMQ and nanomsg are like raw socket toolboxes.