Actually Armin's video is a bit misleading. He claims kite increases camber when its AoA is increased, even though his drawing suggests that is not happening. And when decreasing AoA camber is claimed to decrease for bigger positive momentum, again picture does not prove it (Armin draws a low cambered airfoil out of his head).
It is true in FS kites camber is indeed increased/decreased, but Armin does not explain why and his drawing (although exemplary) does not prove it, but more like disproves it.
I'm not sure if it is that kind of videos which had caused so much confusion among some bridle tinkerers. Some have messed up quite bad three different things which happen (or not happen) when bar of the depowerable kite is sheeted in/out. These three are:
1) kite changes AoA
2) kite changes camber (if it is designed to do so)
3) some mixer adjustment (preset) for camber is in effect
Only 1) is elementary for powering up/depower, it is always there if kite is depowerable. 2) is a useful invention, but kite works well without it and 3) is mainly a method to get kite back to its original tune, to counter line length variation.
3) has some potential to adjust kite for personal taste/use, but when doing so some other properties of kite will suffer. It is foolish to think to get a decent kite generally better by tweaking the mixer. No matter how many hours tinkering is done PanshA15 will not become Soul - opposite is very possible though