It stops me sitting there hitting refresh on a web page to check my stats every 45 seconds.
Smart man. Aside from customer support information, everything on my dashboard is cached for 24 hours. I do this specifically because I used to waste far, far too much time sitting on Google Analytics mashing refresh. Mashing refresh on the dashboard just shows me the same thing I saw that morning. (I have a URL available which forcibly purges the cache, but it requires me to type in something like i-have-nothing-more-important-to-do-than-this in my URL bar. I think I've used it maybe twice.)