They are not designed to do an instant jump, they just allow you to slowly charge the battery and/or get enough power to operated the electrical systems like doors, etc.
And they do work to get enough power to start the car. My SRT battery was dead and I used ours to get enough charge back to start it. It took about 20 mins of connection before it fired up.
That would be a good way to get a 'jump' when using an AGM. Didnt watch the video, but a slow recharge would keep the battery from getting hot like it does if you just get a straight jump and then drive it with alternator doing the recharge.