The tablet daemon runs in the background and does the ground work. Detecting the tablet and set it up with the selected profiles. If the daemon is not running the System Settings module and the plasma applet cannot work properly and the tablet cannot be used with the profiles.
The detection of the tablet device is done in several ways. Solid is used in the first step and does the hotplug support. If Solid fails the next steps are xsetwacom list dev, lsusb and xinput --list.
Should none of the commands above return the name of the tablet, it is not supported and cannot be used by this module.