What's the reason for not telling people that buttons marked with two labels (leftmost and rightmost) have two functions, one immediate and one delayed?
What's the reason for calling it the ZOOM button all the time, when you do use the second function, which is clearly labelled on the flash with the remote transmission icon (Z-shaped arrows)?
Why, in a video like this one, do you not at all tell people to put the flash on the camera and use the camera's menu system to set up the flash? Especially when using a more advanced function, like the remote master setting, this is a lot easier for beginners. Not always faster, but always easier. We've had that function since the 1D Mark III.
Once you've understood what it is you want to set up on your flash, you just have to learn which button to press, not what to accomplish, if you indeed want to use it on some older camera, without menu support, like a 5D or a 400D.