No. They are useful as a representation of the overall effort one has to make. The effort made in ascending 500 metres is not recovered when you descend 500 met

No. They are useful as a representation of the overall effort one has to make. The effort made in ascending 500 metres is not recovered when you descend 500 metres. Ascending 1000 m continuously along a 10 km trek is significantly less effort than ascending and descending five 500 m hills along the same distance, even if in the first case your end point is 1 more km above sea-level than where you started, while you remained at the same altitude in the second case.