Checklists are valuable for several reasons. They can help with organization, completion and collaboration.
To begin, the act of creating a checklist helps us to break down a task and ensure that we have the tools or skills needed to accomplish the task. As we list the steps of the task, we are thinking about how to accomplish the task; if we are going to build a bookshelf, then as we think about assembling the pieces, we are going to realize that we need a hammer, nails, etc.
A checklist is valuable as a tool for making certain that we are not missing a step along the way, this can be especially valuable if the task cannot be completed in one session; the checklist will allow us to see where we were in the process when we stopped the last time. For this reason, a checklist can be invaluable if we have to hand a project over to another person.
If we are working with others to complete a task, a checklist allows us to easily assign portions of the project so that we do not have people unintentionally duplicating work.
Checklists also work as a form of positive reinforcement. There is satisfaction in checking off a completed task. It can also be used to set a challenge for yourself, either on being able to complete a certain set of tasks in a session or being able to complete a task within a certain time window.
Overall, checklists are extremely valuable if they are created and used thoughtfully, I will note however, that if you take the time to create checklists but do not use them, it is actually a waste of time that only serves to create an illusion of organization.