When would I ever need to "peek" at my desktop?

[Annuit Coeptis]

Windows 7 offers multiple ways for one to take a "peek" at their desktop. It is called Aero Peek.

• The hovering over the button in the lower right corner
  
• Windows key + spacebar
  

My question is, why would I ever need to do this? What purpose is there in viewing the desktop temporarily?

To me it seems like a useless feature and a waste of precious taskbar space.