TL;DW: It's solid advice. Insulate the crap out of the space around the unit since the default spacers don't seal/insulate well and let a lot of outside air mix in. He just goes above and beyond how most people would do that.

I thought it was going to be something wacky like stick a magnet on it or something, but he shows how to use a plastic sheet, spray foam, and a foam insulation panel to make a good seal (without the spray foam getting stuck to everything) that also looks good. I've used pool noodles in the past, but this seems like it would insulate even better.

I gotta say, he was a trip to watch. If you have 10minutes, give this video a watch it was funny. Otherwise, Admiral Patrick was on point with the summary.