I didn't watch the whole video but based on the article, it appears this guy is just putting up christmas lights using off the shelf hardware and software? He isn't hacking anything here and this hobby is already pretty common anongst those with the money and electronics experience to build it.

Tom Betgeorge works in this industry and is pretty renowned for doing massive displays using all this same stuff every year and uploading it to Youtube.

Unless your lights are hard-wired or connecting to a locked down guest WiFi network, you are exposing your WiFi credentials to potential attackers.

The microcontrollers that control Christmas lights are riddled with backdoors and holes.

That’s probably the real reason that this piece of shit NSA spook wants everyone to have smart Christmas lights.