Um, anyway, we have been playing with knives, and I figured it would help me to be able to review the lessons, slow them down, like that, to see what blew past me during class.
(And before anybody asks, no, I'm not posting any of them, not here, not on YouTube. If my teacher wants to offer such things, that's his prerogative, not mine.)
It is useful, to see it played back in slomo. If you are studying an art and your teacher will allow it, consider the notion of taking a video now and then. Way better than notes, a picture being worth a thousand words and all.