Where to start? Aside from what could possibly go wrong, I should reiterate that the weight is way too light for the demonstration. Let's put it this way. With any kind of light weight from any equipment, anyone can make up any kind of exercise and make it look good. A kettlebell is not a dumbbell. You can't expect movements that works for a light kettlebell to work as well as a heavy kettlebell. You would expect those things to work for dumbbells and barbells because those tools are symmetrically balanced. Regardless of weight, the dumbbells and barbells have the same center of balance.

Kettlebells don't, and this is more apparent with hardstyle kettlebells. There is a reason why pro grade kettlebells used in girvoy sport are the same shape and size. If they weren't, then all the giryaviks who participates in the sport would have to spend time to relearn how to handle the kettlebell as they get heavier.

So with the actual chop itself, you run the risk of biffing your knee. Your only control over the kettlebell is on the handle. The bell is left to swing freely on the way down. You can't stop the swing of the bell just like that. You can't just tighten your grip and expect the bell to halt mid-swing.

Also, if you allow the bell to swing down like that, then expect the bell to travel back up in the exact same path. So you also have no real control of the bell as it travels back up into the rack position (best case scenario is that it leaves bruises on your forearm; worse case scenario is broken bones). That's a no-no in kettlebell basics. You don't allow the kettlebell to swing out of control.

The cost of failure for this exercise is too great to be recommended for anyone. A better substitute would be to perform the same movement with something like a dumbbell or a medicine ball, where the tool is unable to swing out of control.