I've been using one of them for a while now. Far better than a traditional chain whip.
AND I roared with laughter at the "Ice Tools Chain Hook" in the same film - do people buy them?!?! - I have a an old spoke bent into a similar shaped "tool" - cost me nothing (in fact I made one for a customer yesterday in about 45 seconds - cut a spoke to about 150mm, bend to a 2 sided triangle, bend two ends with a pliers to make hooks for the chain - that's it!)
Rob
I've yet to fail at the shop with one of these : https://www.parktool.com/product/sprocket-remover-chain-whip-sr-2-2?category=Cassette & Freewheel
... and these are good too: https://www.parktool.com/product/chain-whip-pliers-cp-1?category=Cassette & Freewheel - one of these also makes a difference : https://www.parktool.com/product/freewheel-remover-wrench-frw-1?category=Cassette & Freewheel
I like Park Tool products! - simply the best.
Rob