So we have just the next question: If it's message passing, why was it build on top of HTTP? Wouldn't a RPC-like protocol as base be much more adequate?
This would just strengthen the suspicion that this protocol is badly designed, to be honest.
Because HTTP is ubiquitous and passes through every firewall around, and has extensive tooling. You need a really good reason to pick a different choice if you're going to expose your endpoints to the public internet today.
