Well, not exactly the same...

If you move the script when you have 'use lib' then you might need to change the script... (ofcourse this is not true when the path of the modules-directory is relative to the path of the script path, but that's not always the case)

And ofcourse one can argue wheter or not user-independene is required... if many users are using it then it might be better to put it in a INC-dir (in a subdirectory ofcourse)

It all depends on one needs... which is why I mentioned it, since not everyone might know about the variable... (which would indicate that they didn't read (or skipped some parts) of the perlrun POD...)