I totally can imagine what a huge potential semantic technologies such as knowledge graphs, ontologies, SPARQL search and automated reasoning might have in different fields of science and engineering. However, apart from biology and medicine (which I have only very little insight on) they seem to be rarely used (e.g. compared to machine learning methods).
Of course it is likely that I am simply unaware of very useful applications of semantic technologies, therefor this question.
More precisely, I am interested in short descriptions which concrete knowldegebase/tool is used and which problem it helps to solve or which question it helps to answer.