This comprehensive level of extreme tuning is not going to be directly useful to most people; but there are a few things in there like SO_ATTACH_REUSEPORT_CBPF that I hope to see more servers and frameworks adopt. Similarly I think it is good to be aware of the adaptive interrupt capabilities of AWS instances, and the impacts of speculative execution mitigations, even if you stick to the defaults.
More importantly it is about the idea of using tools like Flamegraphs (or other profiling tools) to identify and eliminate your bottlenecks. It is also just fun to experiment and share the results (and the CloudFormation template). Plus it establishes a high water mark for what is possible, which also makes it useful for future experiments. At some point I would like to do a modified version of this that includes DB queries.