I would like to point out that any blockchain like thing with some kind of coin/token with value could be used for this. Like in theory this could be done with Bitcoin it's just very very slow and due to the rather high transaction fees its probably not really interesting.
After years of being interested in blockchain tech and hundred of hours research this is the only real world use case that is deployed, used and most importantly generally makes sense, that I know of. There are a bunch of other projects like Brave that are technically deployed and working but IMO do not solve a problem just recreate the existing problem with a fancy token.