It predates the LLC era, but this was how Disney bought up its huge swaths of land just outside Orlando to build Walt Disney World.
http://www.latimes.com/business/la-fi-disney-shell-companies...
http://www.latimes.com/business/la-fi-disney-shell-companies...
This is definitely the most common reason for anonymous LLCs. For elaboration, think about buying up a ton of crappy property in a specific area. Doing it all under a single LLC with traceable names can cause property agents and banks to notice and raise prices / hold out on existing property that the developer may need.