This really confused me. Even if you power it from your monitor you've got to plug it in. No shame in having one or two cords, so why fake the product shots?
They could have at least set up the shots to imply the cords were just hidden behind a table or something.
My thought was that one of the modules had a plug on the bottom so you could run the cables through a hole in a wall/desk... but it looks like none of the modules, not even the VESA mount, have anything like that.