A bit confused. Is this for tunneling localhost like ngrok ( https://ngrok.com/ )?
The big difference is when you are inside your local network behind the router, or at work behind a firewall simple accessing the wan-ip won't reach your machine, unless you do port-forwarding (which isn't always straightforward or even possible.)
Ngrok solves this problem by being in the middle, both your machine and a person visiting alias.ngrok.com are connecting to ngrok, ngrok just passes the data along.
What this service however is good for is to have a dns address that always points to your local machine or your home network if your ISP doesn't provide you with a static ip (thus your ip changes every so often).