When I did not know how to program, neither async nor message passing were intuitive. I had to learn, and now those are tools I can use when they make sense.

I never thought "programming languages are a failure, because they are not intuitive to people who don't know how to program".

My point being that I don't judge a tool by how intuitive it is to use when I don't know how to use it. I judge a tool by how useful it is when I know how to use it.

Obviously factoring in the time it took to learn it (if it takes 10 years to master a hammer, probably it's not a good hammer), but if you're fine with programming, state machines and message passing, I doubt that it will take you weeks to understand how async works. Took me less than a few hours to start using them productively.