The Dutch case is the “strongest climate change decision ever issued by a court”, from The Guardian.
Sometimes, Governments promise large actions in favour of the climate, but they do not always follow up, if left unchecked. Then an action in court can move things up a lot. See the article on https://www.theguardian.com/environment/2020/may/04/climate-action-under-duress-how-dutch-were-forced-into-emissions-cuts?xing_share=news