Netcat is also able to be used as a Forwarder and Relay.
I am not going to go into detail here, but if you think about it, there is no reason why a single netcat listener is the end of what you can do. Chaining netcat can allow it to pass multiple layers and systems. In Pen-tests, Red Teaming and even on the darker side of the fence, this techniques os used to "drill" through firewalls and security systems.
More than this, netcat can chain across different protocols. It is possible to pipe one connection type into another. This is, a connection to DNS (UDP 53) can be changed to HTTP (TCP 80) etc.
All of this just touchers the surface of what netcat does. I would suggest that you search and find out more. Fell free to post comments - there are always more uses of netcat and the other readers would love to read yours.