What is the difference between Windows Updates and Windows Updates Approvals?
The Windows Updates page only shows the updates that are available and not yet applied.
The Windows Update Approvals page show some of the recently applied updates, but those covered in cumulative updates or other major updates of the OS seems to be hidden by the WU API, because these larger updates already include the smaller more specific updates. The data shown is based on the Windows Update API and should closely reflect what you see in the local UI of the Host.
So the Windows Updates page shows the current status of windows updates across the environment, while the Windows Update Approvals gives the user options to apply or block updates.