These are just the details I gleaned from the article. But, I have a similar understanding... that the blockchain functionality is similar to self-signing.
The article bills Vapor as helping to decentralize the "data layer" of an api. This naturally has some immediate caveats... like... this sort of framework would not be suitable for real time or streaming Apis.
Also, the article doesn't really touch on the cost of maintaining all of this. It's true that vapor api hosts can charge a small transaction fee to maintain/run their processing nodes. I have to wonder what that looks like, and if people are willing to pay a per-request fee for an http transaction.
I don't believe this is intended to replace standard authentication, and calling out how it's impractical for common scenarios is fair game. However, I think it's more interesting to think about scenarios where this might be useful.