Contour lines are really useful to anyone going out into the hills who uses a map to navigate as they’ll give you lots of information about the ground you’ll be walking over. Being able to visualise the terrain from the information on a map is one of the most useful skills to have before you set off for the hills.
With a little practice you’ll be able to imagine what the ground will be like and use that information to make an informed decision about your route choice.
Link to the history of contour lines which was mentioned in the video:
https://www.youtube.com/watch?v=hRNyS5MBfGo