I love it when a 5 minute method takes 12 minutes to explain. These search queries have nobody looking for them, and thus they have nobody ranking for them. Essentially this method can work for all super low lying fruit, but is unlikely to work for say "Payday Loans UK." It is unlikely to be patched soon in my opinion because despite how easy it is ... a very small number of people overall are going to pursue it.
Now I do wonder if this used in conjunction with some other strategies might strengthen it overall, and start to be able to reach for some more competitive keywords, but ... Big G is watching, so I doubt it would work much better in any other SEO configuration or combined strategy. More likely it would just out a footprint or point light in a direction nobody wants for their sites.
There's no need to hide this away. While it can work on some things, it's simply unlikely to change the world soon despite being an easy way to rank for terms that there are 1,000 other easy ways to rank for. For example, you could simply create a video on youtube for ANY term that has no search data and no competitors targeting it, and simply indexing it would get you #1. I think there's a reason not too many people try to rank for this low lying fruit, and that's because it's not all that tasty the way scarfing down a handful of "nevada divorce attorneys" would be.
It works though as OP illustrated, so I'm sure some smart folks can come up with a viable usage scenario. For example, is this the mechanism through which folks in the movie niche get their sub-reddits indexed so quickly? Is it necessary in this scenario to keyword stuff the actual content posted on the sub-reddit? Ref:
https://www.reddit.com/r/latoki/.rss <-- Any link to the sub without a DOT qualifier at the end will always simply show a clickable link but with the .rss qualifier we can see what the poster has stuffed into the content of the post itself.
These people use a custom .css entry to make the image clickable. I'm sure you can find that if you look around hard enough, or you can simply de-compile it from research. It's nothing earth shattering. The question though is really ultimately one of .... can this work with more competitive keywords using a keyword stuffing approach on reddit, or is this simply a function of the type of niche this is?
Good post OP!