In Windows you can save "virtual desktops" with different configurations of programs for different tasks. Workspaces in Help+Manual are similar. They allow you to save the "set" of projects you are currently working on to a file so that you can then reload it in one easy process, instead of manually re-opening all the projects.
In addition to the open projects workspace also stores and reopens all open tabs and remembers the last topic you were working on in each project.
The innocent-looking Save/Load Preferences option in the View tab hides a very useful feature. This tool saves all user preferences, license key, keyboard shortcuts, recent projects, recent workspaces, Quick Access Toolbar settings, pinned projects, syntax highlighter configuration and everything else that you can configure to plain text file. You can use this to load your desktop settings on your laptop computer, for example, or for restoring all your settings when you are upgrading to a new computer.