Agree with edt, it is maybe the worst way to untangle lines.
They even show "if you do it wrong", so you have to do it twice the other way, yiaks - doing this say out in the waves in the background, that is calling for BIG trouble
And you can not see which way it is as they cross so high, so only 50 % chance you get it right, so half the times you have to do it 3 times to fix it
Ride ashore and get it fixed, instead of risking yourself and your gear - easy
Also, it is only possible on bars with a super low V, not with a high V of course, but not safe either on bars with a bit of short leader/knot line above the depowerline as many has.
I would not do it on the water and can defintely not recommend it, but each to their own
PS: It is good to know how it CAN be done, but would still not recommend it, particularly not for those not knowing how and seeing it for the first time....