Even if there's no use for it right now there might be in Legion, right? The Landslide buff is obviously irrelevant because there is just absolutely no way around pressing Rockbiter/Boulderfist once every ten seconds but if Crashing Storm should not be the ideal talent or maelstrom regeneration is too slow or GCDs are too limited for whatever reason you're suddenly looking at the possibility of wanting to press Crash Lightning just to maintain the buff and not on CD.