Pan and zoom guides the viewer across a larger screen, revealing one area and then another. Moving from one stop to the next can preserve the overall context while making details readable.
In an editor, record position and scale at the start and end frames, then interpolate the path. The demo travels between two stops on a larger board.
The Ken Burns effect also pans and zooms across a still, while pan and zoom often emphasizes a guided route through several areas. Too many sharp direction changes make that route hard to follow.
When to use
Use it to explain a map, large capture, or diagram that cannot fit at a readable size all at once.