I thought about the same thing myself. But somewhere on TB I think I read that the input is tailored or designed for the output for a GK MB112 combo. It would be great if they could run straight out of the pre-out and daisy chain from one powered cab to another.
That's exactly how they work. The combo amps and powered cabinets both have seperate 'chain outputs' so you can chain together as many as you can stand.