Many organizations fail to appreciate the value of project prototypes.
They give a functional if rough implementation of a project in much more granular time frames. More granular time frames give more accurate estimates from a project planning perspective. In most cases, this results in a shorter time to publish.
Furthermore, this allows the development team to confirm that what the business requested is what it actually wants, and equips the business to request specific changes to an already functional base product. Many business representatives may have trouble envisioning specifics about a product from documentation or marketing material. Seeing and using a practical implementation is substantially more concrete and provides the opportunity to suggest altered functionality from the prototype.