Reducing work-in-progress helps optimize flow by:

Reducing work-in-progress helps optimize flow primarily by creating focus. When teams limit the number of tasks they are actively working on, they can concentrate their efforts on completing those tasks more efficiently. This focused approach minimizes context switching, reduces the time it takes to finish work, and leads to improved quality since team members can dedicate their full attention to each task at hand. By promoting a clearer sense of what needs to be accomplished, teams are able to enhance their productivity and ensure a smoother flow of work.

In contrast, pursuing multiple goals at a time can lead to divided attention and slower progress, while preventing priority changes might hinder the team's ability to adapt and respond to new information or shifting business needs. Respecting the timebox is an important aspect of time management in Scrum, but it does not directly contribute to the optimization of flow through reduced work-in-progress. Instead, focus through limiting unfinished tasks is a more compelling and effective strategy for achieving better flow in the work process.