There are sometimes funny height definitions in some sources: I found one from South Korea in the internet, which said that the height of Stuttgart TV tower (
https://en.wikipedia.org/wiki/Fernsehturm_Stuttgart ) is 391 metres. They measured the height instead from its base from Schlossplatz (
https://en.wikipedia.org/wiki/Schlossplatz_(Stuttgart) )!
However height definitions of man-made structures using sea level as reference seem to be from some importance in aviation, as these values are published in most official air-traffic obstacle lists.