@Thomas : The Pause/Resume feature mainly allows not to stop current track AND to continue to track satellites in the meanwhile (locking enough satellites to get your position can actually take a very long time, especially with N900 hardware).
Using example : You stop for lunch during a road trip. This is faster and more convenient than starting a new track (or even appending one to an existing file since same process is involved internally).

You can upload your KML files to http://maps.google.com to visualize your track. Click: my maps > create new map > import > browse and select your file. Alternatively can upload your file to http://www.gpsvisualizer.com/