It also has a screenshot feature. If you direct your browser to the Wii's IP, you can download a 640x480 image of what's on the screen, IIRC.
When people tried to validate games on a Wii and then use Devolution on Wii U, they usually had to not only bring the Wiimote along but also the SD card. If you copied the image and DVV to another SD card, the DRM check would fail. Devolution also seems to verify the game's TOC against the DVV every time you boot, so you can edit individual files in the disc image, but if you replace files with new ones that are a different size, it changes the TOC and trips the DRM, too.