in theory yes .but in practice because of the poor reverse voltage and current ability it would not last long.I suggest you try watching the video again , he explains it all in his narrative.

 

The advantage of using AC is you can use a capacitor for a partial ballast resistor. Reactance is different than resistance, so there is a substantial energy savings (unlike resistors). Read the article in the AAC book on LEDs, it does explain it pretty well.