There is a clear division of labour between the brain and the slip-box: The slip-box takes care of details and references and is a long-term memory resource that keeps information objectively unaltered. That allows the brain to focus on the gist, the deeper understanding and the bigger picture, and frees it up to be creative. Both the brain and the slip-box can focus on what they are best at.
The permanent notes are your elaborations. The permanent notes gives you something to reference when you remember thinking about an idea in the past. The brain keeps the gist of those ideas so that you know them, if not the details.
