Multiple comments thus far have said that use Order is essentially a no-op, because the calling code will have already included Order. This is guaranteed if and only if every sub in X will be used - which is hardly a foregone conclusion.

Imagine, if you will, that package X has defined both sub do_something_to_order and sub do_something_to_customer. If X is then referenced by a customer management application, the app will not be importing Order (or calling do_something_with_order) because it doesn't do anything related to orders. In this case, leaving use Order out of package X will prevent Order from being (needlessly) included.

I don't think this situation is much of a stretch if you're talking about modules which are used in more than one place. When was the last time you used a (non-trivial) CPAN module and your code (directly or indirectly) called every single sub present in that module?