Nice thing about those designs, is that you don't need to accelerate the motors/wiring back and forth. Giving better acceleration rate per unit of motor.
The downside with those systems, is that they tend not to be stiff (due to large amounts of belting), or react to external forces well.
That (H-bot/Core-XY) design would be poor for a convention CNC router, that has to react the forces associated with conventional machining.
But for this application, it doesn't matter. The forces acting on an extruder are basically non-existent, with the exception of (the mass of the extruder * its designed acceleration rate).
For going that fast real time, it might have some trick servos, or a hybrid motor (Search for Technic ClearPath Motors).
If you like that video, then you might like this one.
https://www.youtube.com/watch?v=NgGiu_0x7tg (Note: Not afflilated with that company, just like the video)
From what I can see, this printer appears to use stepper motors too. I'd believe it's real-time.
The X axis is held in place vertically by the 2 shiny metal rods you can see, and is dragged back and forth by the black rubber belt, which is controlled by a stepper motor.
The rate at which it jumps around is just ridiculous though.