[2] The claimed advantage of count singing is that it simultaneously teaches both pitches and rhythms.
On the other hand, it can take more mental effort to count sing, particularly for singers who have little experience with it, and the effort of remembering the correct syllables to count with can be a distraction from reading the music or singing it correctly.
Count singing requires analyzing a piece or section of music to determine how to subdivide it.
Count singing provides an easy way to help singers internalize the desired rhythm of a piece of music.
The director could tell the choir to stress the "one" and "four" while singing the other notes lightly, to emphasize the duple meter: "ONE two three FOUR five six".