Not just local disks. Currently, it only allows wiping local disks, thankfully including removable drives. But why not also allow wiping a network drive?
This would imply creating a file (let's call it "wipe") and writing random or data or zeros to it. Of course, the MFT cannot be wiped on a network drive, but we'll have to take that as a given then.
Currently when I need to wipe a network drive, I just create a truecrypt container on it that fills up the available space perfectly, and then delete it. But this is not wat truecrpyt is meant for, of course.