Visual Planning allows you to see information or schedules from multiple perspectives, such as by Client/Jobs or Staff or Machines, etc. This is simply not possible in a Spreadsheet (even with complex Pivot Tables) or on a Whiteboard.
A Workspace orders resources, events, and all related information based on the key dimension being used, e.g. Jobs. This then allows you to build filters to suit each workspace, save them for repeat use, configure them to suit different user groups or staff members and to show the information that matters to each user or group of users.