The code looks good. I don't see a reason to change it.
The Select-Object cmdlet selects properties from the networkadapters. @{N="VM";E={$_.Parent.Name}} is a calculated property. It is a PowerShell hashtable that contains two key-value pairs. It is short notation for @{Name="VM";Expression={$_.Parent.Name}}. The first key is Name and the first value is the string "VM". The second key is Expression and the value is the scriptblock {$_.Parent.Name}.
$_ is the current object in the pipeline. $_.Parent is the Parent property of the current object in the pipeline. In this case it is the Parent property of a networkadapter that contains the virtual machine object. $_.Parent.Name is the Name property of the $_.Parent property. Because the $_.Parent property contains a virtual machine object, the $_.Parent.Name property contains the name of a virtual machine.
I hope this exploination makes it clear to you.
