alias command you can point your own domain name to any now deployment. In this lesson I'll actually buy a new domain name and configure it to work with now, showing you every step along the way.
Think of your alias as your production endpoint. Every time you want to deploy the current version to prod, you alias. But you don't have to, especially while iterating. You can test it on the generated URL and only alias when you're happy with the current version.
You could also have a staging alias, etc. Aliasing is just useful to point a name to a specific build. Do that when it makes sense for your name to point to a new build, whatever your workflow. Does that make sense?