Looking at Copy-SPList Doc, wasn't sure what to provide for IncludeDescendants as it says type should be Nullable``1
On file /POWERSHELL/Help/Lapointe.SharePoint.PowerShell.dll-help.xml I eventually found possible values None | Content | All, however nowhere in Documentation to be found.
Probably some content from SPIncludeDescendants MSDN page (which I somehow found out) could be used to describe this param?