I have characters that have just joined the campaign. I want to make an article for the character that I can use to track them. For example my one player has made a character that wants to find their grandfather. I want to go in and add those notes to their dossier so I can remember that note about the character.
It allows me to have some notes on each of the members of the party that I can use to generate hooks for adventures. The player may play into it, but they may never give it to me on their character sheet.
If someone leaves for a time, says they go in for surgery, and can't play for weeks, it would be a great tool to keep the character somewhat active in the campaign.