I'd say performance in this benchmark is inversely related with how nice it is to express business logic in the respective language/framework, and that's a pretty big deal.

For example, https://github.com/an-tao/drogon (benchmark winner) or https://oci-pronghorn.gitbook.io/greenlightning/ just aren't pleasant to work with. For example, compare Green Lightning with http://sparkjava.com/ and look at how much slower Spark is while clearly being nicer to use.

I worked with Netty at work for two years and it was a dream to use something like Express or Flask on the side, not having to worry sharing/disposing ByteBufs, not dealing with the weird in-channel/out-channel abstraction (vs simple middleware), not investigating how async-/thread-safe a given library was, etc.

It just all goes back to trade-offs. You're going to have different considerations if you're building a Caddy competitor vs a complex game server. Another consideration is how horizontally scalable you can be which is going to be different for a forum vs a websocket server.