No, you could use it any way you want. But don't rely on objects, returned from IIS provider always being types from Microsoft.Web.Administration. I wasn't clear enough about it in my previous remark. Currently, if you run get-item "iis:\sites\default web site" | gm, you will see, that returned object is Microsoft.Web.Administration.ConfigurationElement and theoretically you could use it in the script that expects this type.
But in the future those objects will not be from Microsoft.Web.Administration.
--Sergei