They're not actually buying or selling it though, just making it look like they are.
Lets say I run a lunar land registry like this: https://lunarland.com/. I have a friend of mine buy a worthless deed from me for $10, then "sell" it to himself for $10,000. Now $10,000 is the "market price." I then use that transaction as "evidence" to hype the idea that lunar land deeds are serious things, part a growing market, good investment opportunity, etc. In the ensuing tulip mania, I pocket a pretty penny selling a lot more worthless deeds to lunar land. The victims are the people convinced my misleading hype to invest in them.
Now I'm not claiming something like is actually happening here, but the whole thing is fishy and I think it's a serious possibility to be considered.
It is. But if you register it as a sale, you get to pay taxes on "the profit".