Trusting your system
It's hard to keep stuff in our heads. Keeping track of events, todos, and next steps is exhausting. Using a good system to externalise all of this allows our minds to think and focus on what is in front of us.
The test of a good system is: What happens when you fail to write an event down?
If that event is forgotten and missed, the system has your trust.
Ironically it then immediately lose your trust, and such is the nature of trust in systems.