Is there an advantage? What is it?
So that everyone doesn't need to have exactly the same file structure on their hard drive?  import C:\Python\lib\module\ probably wouldn't work too well on my Mac...
Edit: Also, what the heck are you talking about with the working directory?  You can certainly use modules outside the working directory, as long as they're on the PYTHONPATH.
Why is there module search path instead of typing the directory name + typing the file name?