The video explains that they used a neon bulb, which is far more reactive to current changes than standard incandescent.

Incandescent lights produce visible light largely through heat of the filament, whereas neon lights emit by passing current through the gas, meaning that rapidly changing the current is more effective- the had e doesn't need to cool down like a filament to stop producing light.

I think the video said it was a neon bulb, which reacted "fast enough".

A neon tube was used on the receiving end because it reacts more quickly to current. This is mentioned at about 6:45 into the video.