The user context is accessible with a single click on your user icon in the top right corner of the Seamless Add-In. It's a central navigation element that enables the current user to easily access his most relevant workspaces, documents and tasks. It also gives you direct access to your personal Office 365 tools such as Delve, OneDrive, Outlook, Planner and Tasks.
The user context contains the same information as the Seamless overview. For the daily use of Seamless it is easier to use the user context to change between workspaces the navigating back to the Seamless Overview as no page load is needed.