In MA it's required I'm told

Yea I saw that and was curious about it too

If you ever do any detail drawings for the engineering in a building, you're likely to see that alternating J-bar detail a lot. I still remember the days when they would call for a keyway instead of rebar verts! Ha

I have the same question. @9:39

It's most often used to provide an earth connection for lightning protection systems, but it can also be the earthing system for the home's electrical installation. Rather than drive a single earth rod into the ground where it is subject to corrosion, the connection to the earth is made via the rebar and concrete footings over a large area. This protects the connection, and generally gives a better connection to earth. I do wonder though whether the plastic used to construct the forms is somewhat insulative and so negates the benefits. Googer Ufer grounding systems for more info.

@@tlangdon12 Thanks for the info. You bring up a good question about the plastic being an insulator.

Beat me to mentioning that. These are supposedly professionals but that's sure not.

That would go on the outside of the footer after the forms come off.

The pipe is laid outside the footer and covered in gravel and filter cloth. You want to keep the clay soil far from your foundation because it holds water for a long time. Gravel and sand will allow the foundation to drain and shed moisture from the floor and walls.