show how the approach you refer to is more robust than Unix pipes.
You can pass objects and collections of objects in the PowerShell pipes.
[Are manual pages] accessible from within the terminal emulator hosting the command line?
Yes. And "manual pages" can be included inside user created functions to behave just like the built in ones. The help information in Powershell can be quite verbose. But it is categorized and the Get-Help cmdlet has switches to show you the basics, certain sections, or the whole content.