Those of us who use a fair amount of choreography with our groups seem to need to learn this one over and over.
As a quick demonstration of the mind bending confusion that the wrong choreo can cause:
As you say the word ‘up’, point up with your index finger
Now say ‘down’ and point downwards.
Now do the opposite – point upwards and say ‘down’, then point downwards and say ‘up’ – and notice how much more concentration it takes.
When a choreo move is in sync with what’s happening musically and lyrically, we don’t need to use up a whole lot of brainpower getting the move right. What this means is that as we are performing we can still keep thinking about emotionally selling the song.
Of course, it is possible to rehearse and rehearse the move until it is being handled by Muscle Memory ( https://betterchoirs.wordpress.com/2012/05/04/magic-choral-trick-131-training-wheels-and-muscle-memory/ ) but if it’s not exactly right for the singing that’s needed, the vocal tone will always suffer.
As an example – it’s very difficult to sing legato when the move being asked for is bouncy. Yes, it can be rehearsed and rehearsed – but even when it’s right it will still feel off to the audience. They may not realize what it was that they didn’t like – but they will have been distracted. At that point neither the chorus nor the audience is able to revel in the sound or the emotion.