It’s true the term “Blitzkrieg” does not come up often in German plans, old memoirs, or communiques. It’s closest word or phrase that the Germans/Prussians may have used more often was Bewegungkrieg or maneuver warfare. The term Blitzkrieg however pops up more post-war to describe the tactics of their Wehrmacht during the WW2. But to be honest the Prussians and later Germans have been practicing these kind of tactics for years and the end result was this form of warfare during WW2.

The reason Blitzkrieg is so prevalent when talking about the Germans is because it’s a buzzword that most people recognize and can understand automatically.