I learned of them fairly recently as well, also on Net54. It goes to show that some people will collect anything. It is kind of weird that anyone would want them, but they are fairly limited. Still, collecting cards of random children (and paying large sums of money for some of them) is odd no matter how you look at it, even if they might be considered part of an extended Topps set.
I did not watch the video the first time, but just finished it. $35K for the set of 19! WTF!? Am I alone in thinking that someone dropping nearly $2K per card on average is just insane? Some people seriously have too much money. I think everyone understands that buying trading cards is a niche to begin with, and everyone collects what is most interesting them, but I have to assume that the buyer is some sort of set or Topps completist. I can't believe they care about who the subjects are any more than they would when checking off boxes on a regular Topps set checklist. All the kids wanted the big players and many wanted home town favorites, but there were always cards kids hated to pull or just didn't care about, except to complete a set. Mine was Bob Apodaca in the 1978 Topps set. Hated that card. I might have been willing to spend a few bucks to have one as a novelty, but it appears that unless I befriended a former winner, who still had their cards to give out, I am not likely going to own one of these (since they are worth next to nothing to me) and I am perfectly OK with that.
There is one on ebay, as far as I can tell, for $500. 1972 is one of those sets that has seriously committed fans, so I wouldn't be surprised if that was the going rate for these things but to a novice it seems pretty high for a niche within a niche.