Simple. Updates, particularly FW, have not always proven benign. The famous Dec 10 FW update is a case in point. Hence the advice to not automatically apply updates until shown to be safe.Just wondering why you say to keep automatic updates turned off?
Actually this has been my policy for a long time, with diverse OS/platforms. Comes under the heading, "if it's working don't try to fix it". On my SP2, I have the update setting in place to notify me of new updates, and after review, I'll decide which to then download and install.