The Ctril+Alt+Del is in what is referred to as a Windows Command Key group or Sequences. Some of these Command keys will work when set up on your Quick Keys, Tablet, or Pen buttons, but most will not.  For instance, Win+E brings up the file explore and can be assigned as a keystroke on a button with your Quick Keys, Tablet, or Pen. 

Win+L cannot be, and more accurately stated, it can be entered as a Keystroke, but it will not be triggered when pressed. Instead, the operating system will stop it from exiting the command.

We do not have a list of the Command Key groups that will or will not work when assigned to a button on your Quick Keys, Tablet, or pen button.