[WBS is an amazing tool in the project management paradigm. It shows a hierarchical breakdown of work activities that are used to define the scope of the project. It is also used to identify all of the required deliverables that are needed in the development of the project.
Having all these details spread out in the open enables not just the project managers but also all the other stakeholders to understand the project scope. Also, it helps the teams to understand exactly what needs to be developed.
The beauty of WBS is that it divides the project deliverables and the work required into very small components that are easily manageable. The lowest level items also known as Work Packages can be monitored, assessed, controlled and easily cost estimated.