There's a similar concept in PhD programs when they make you present a timeline for future research. Every grad student knows that over the course of 2-5 years things will break, experiments will fail, people get discouraged, interests change, money runs out, whatever...but for the sake of completeness and forethought, they require you to detail future milestones. This stage of planning proves to people that you are committed to what you are doing and are in it for the long haul.