Would you rather personally take your idea to YC or ZD? Which of the two do you think would be more successful in the long run? Which environment will actually motivate the "founders" and stimulate them to create something great and useful?
Area 120 is awkwardly addressing the fact that 20% time is dying and isn't working as the R&D model that once drove so much innovation at Google. The name itself is an in-joke about the tendency for 20% time to only come after you've done the first 100%.