Useful, and I like the ability to disable F12... but I prefer the "Stop Dashboard" widget.
http://osx.iusethis.com/app/stopdashboardwidget#opinions

Because it's easy enough for me to not hit a key. I do kill it occasionally, though, as some of my widgets update themselves in the background, and some are process-hogs when they do. It provides a handy way of doing that, while still leaving the Dashboard functional on command.

True, but I prefer to disable the Dashboard altogether to prevent accidentally starting it up.

I don't understand the purpose of these utilities. Ya know, if you simply never activate Dashboard, it doesn't use any resources.