when he's filming he records video (camera) and audio (microphone) separately. The clapper board clap will make it easier to sync up the video and audio later in editing.
This is the reason for clapper boards generally.
Why does he leve them in? Don't know. Cinéma vérité? Is that the right phrase?
(, Thu 1 Jul 2021, 9:32, Reply)
A lot involve him walking and talking, then arriving at his destination (or the point) at the right moment.
I reckon that could be why his delivery can seem odd. Trying to get the timing right.
The clapperboard bit is probably to emphasize that it is one take.
(, Thu 1 Jul 2021, 11:39, Reply)
Although, for the record, I don't find his delivery to be odd.
(, Thu 1 Jul 2021, 11:57, Reply)