SW2009 SP2.0 ROUTING -virtual pipes and routes

Andy,
Please, explain why do we need the virtual pipes and routes?


I copied from SW2009 Help:
Virtual components are saved internally in the assembly file inwhich they are created, instead of in a separate part file. Whenyou create components in the context of an assembly, the softwaresaves them inside the assembly file as virtual components. Later,you can save the components to external files or delete them.
During the conceptual design process, when you frequentlyexperiment with and make changes to the assembly structure andcomponents, using virtual components has several advantages overthe bottom-up design method:
You can rename these virtual components in the FeatureManagerdesign tree, avoiding the need to open, save as a copy, and use theReplace Components command.
You can make one instance of a virtual component independent ofother instances in a single step.
The folder where you store your assembly is not cluttered withunused part and assembly files resulting from iterations ofcomponent designs.
To save a virtual component to its own external file,right-click the component and select Save Part(in External File) orSave Assembly(in External file).
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