Taking notes is a pain and trust me it can be time consuming. Despite the extra effort there are a few good reasons why a person who might want to keep notes on major activities and work they are completed. When it comes to justifying a position or moving projects forward it will be those with the notes that will step ahead of others.
Memory is sort of hazy after a few months. It is helpful to keep notes so that you can remember what actions you are taking and where you are on any particular project.
You may have had conversations you need to remember so that responsibilities, completed components and other check off items are noted.
It can be beneficial to file away your notes with the project when completed. This way you can review to determine the best methods for managing future projects.
You may also want shared notes so that others on the project can update when they complete something as well. This leads to participants knowing exactly what is happening in real time.