Interesting, but massive overkill when you're transferring assertions between two parties where only one party (the server) is allowed to create the assertions.

In the examples in the article, the JWT header is just plain cruft because you're unlikely to be switching encoding often (and if you decide to, including a single much shorter token as a "stand-in" for the bloated JSON data would be much better; using JSON).

The payload also represents a lot of extra overhead unless you intend to transfer more than just a single level dictionary.

It's kind of comical that they present it as "compact" given that probably something like 30% of the length of the presented example is unnecessary.