A while ago we decided to unify all of our addresses in the customer account and lower the processing time of review order shipments.
The feature "Preferred shipping address" for review program was removed, so now when you place an order with review assignment, you select the shipping address directly from recently used address list or enter new one. The old “preferred shipping address” was required since an order was submitted by administrator and administrator had to know the address. In new system you set the address in the checkout and your order goes straight to the warehouse without the administrator.
The address settings were added for your convenience in order to show all preset addresses in one place for all your gift registry lists and affiliate account.