Huge example of this came on the first South Wales Mountain trial... a leg of 2-3 miles across to the other side of Fan Fawr.
Everyone except for myself contoured round. But i took the steep 500ft climb straight over the summit...
My thoughts were not so much distance saved (i don't think it saved any distance at all), but then having the vast majority of the leg running downhill, approaching the checkpoint from above, and hopefully avoiding the abundant tussocky and marshy ground.
Your own relative strengths/weaknesses also play into it.
Leg 1-2 on the map below...
https://drive.google.com/file/d/1L-C...Z8qWyOaY_/view