the use i had in mind would be to tag polygons with a custom string attribute or two called "start time" and "end time", for use with the maya2googleearth mel script, which I customized to utilze the new time element in the kml 2.1 specification.

it basically allows you to tag points in google earth, with dates, and view the points (and also polygons) in the order of their timestamps.

here is some more information about it, since my explanation doesn't really describe it very well...

https://earth.google.com/kml/kml_tags...#timeprimitive