Well, while New Game +ing is one of the reasons why I want to be able to save and load the item database, that's not the main reason.
The main reason is actually so I can add additional properties to the items, particularly because in the game I'm making I don't want to work with Str, Dex, Agi, and Int(I want to change Dex to Con for defense and add in a Spirit for Magic-Defense), and I want to be able to make equips capable of adding or subtracting from the fifth actor/battler stat.
Additionally, I want to add a few more, 'hidden' properties which would have other effects. If I could load the item portion of the database from a seperate file, then I could just type in all the items in the game into that seperate file and have it behave as if they were saved into the database. Then the saving an item database would come from if I did both item crafting and a New Game+, or something like Golden Sun, or again, it'd be handy if I wanted to make a Roguelike style bones file.
EDIT: Also, I thought of another use; if one extended it to actors and classes, and used the RMX-OS, one could also use it as sort of a DLC-type function, allowing a creator to add bonus-characters or weapons in later if he so felt like it.