How works "location" filter in redwood page

Summary: I would like to request clarification regarding the logic of the Location filter in the Candidate Search page.
At the moment, it is only possible to select countries rather than specific cities, yet it is still possible to define a distance radius (in km).

My questions are:

From which city or reference point is this radius calculated, given that the selection is at a national level?

What is the actual purpose of the “radius” parameter if a specific city cannot be chosen as the starting point?

This behavior seems inconsistent, so I would appreciate further explanation of the intended logic.