In the Shipping Details tab, one has the ability to override the Ship-To Address & Contact, however, one has to manually enter this each time rather than selecting from already existing Addresses within the system.
Example #1, Customer X should be able to have a Ship-To location of all their defined locations, as well as all their defined Contacts...for instance if a shipment was to go directly to a contact and that Contact's details were already attached to the customer, why not allow one to select the Contact as the defined ship-to location vs. having to manually enter it. While one could alternatively define all Contacts as Locations to work around this, please see Example #2 below.
Example #2, Customer X orders goods to ship, but wants them shipped to Customer Y or Vendor Z. In this case, we should be able to change the Ship-To location for the order to either Customer Y's Locations and/or Contacts, or change to Vendor Z's Locations and/or Contacts.
It reduces data entry, entering/storing of incorrect address information, helps with address upkeep (moves/changes), and facilitates using system available data.