It may be basic, but just the _existence_ of this field wasn't something that was on my radar, let alone all the details and implications. This was certainly the most interesting and enlightening set of videos I've seen this year.
I particularly like this one because "I want to get an oscilloscope and see what is actually going on" was my first thought, and this video saves me the effort of trying to set up what would be a much more limited version of the experiment. The promised followups also cover exactly what I'd like to see tried next.
The history of transatlantic cable-laying is extraordinary (and didn't work for several attempts because the theory of the field around the cable wasn't properly understood).
I've been partially following the discussions around the original Veritasium video and all that it's caused, and my thought was basically the same: the masses are just rediscovering what was known over a century and a half ago and that theory has found countless applications in communications and power distribution for roughly as long. IMHO that's not a bad thing, but to present it as something novel is.
https://en.wikipedia.org/wiki/Transmission_line