Player Personal Inventory was created to separate the
Party Inventory which can be accessed by whole player party from the stuff that only player can use. This way you don't have to worry about filling up your
Party Inventory with stuff that is only meant for the player.
There are 3 separate categories for Player Personal Inventory right now:
Quest Items - Items that are needed to complete quests or are quest related in some way;
Documents - Items that you can read such as Books, Scrolls and so on;
Note: Books that the Player Party or companions can make use of won't appear here.
Miscellaneous - Items that don't fit into 2 previous categories such as
Precursor Artifacts, Torches, Lockpicks and so on.
You can use the presentation to select Documents to read, click on Torches to equip a torch and even more things that are coming soon.
How it works:
Items are added to it by various ways [from Chests, Dialogs,
Personal Inventory Trade Presentation (planned feature) etc.], you can't transfer an item between
Party Inventory and
Player Personal Inventory. Why? Because
Player Personal Inventory can take up to
801 slots, which means
267 slots per category so if you could transfer, it would lead to abusive behaviour from the player. What is more, if you got more than one instance of the same item, it won't take another slot. Instead, the amount of items for that slot will increase. Don't worry, you probably won't be able to fill every slot up anyway.
Without further ado, the stuff you're waiting for can be seen inside the spoiler below.
Video Demonstration (scene version):