Once you have this, the only step that separates you from Continuous Deployment is creating another scripts that is capable of using that archive to install the software in the current system. This is the first paradigm, all the artifacts needed to install the software should be included in one or more zip archives. The aim of using PowerShell in a build is to create a single archive that contains everything needed to deploy a new release.
It allows you to manipulate configuration files, remove unnecessary files, copy files from somewhere else in the repository, etc.
The advantage of using PowerShell is complete control over what will be included in the “release” package. I often use PowerShell scripts to package a “release” of a software during a build because it gives me a lots of flexibility.