True, but now threads are involved. Which is totally fine and might be preferable depending on the use case. But for I/O specifically, utilizing select/poll/etc

True, but now threads are involved. Which is totally fine and might be preferable depending on the use case. But for I/O specifically, utilizing select/poll/etc is usually faster, less memory overhead, and you don't need to add the complexity of threads. Like everything it depends on the use case. In my experience, threads are preferable when the API server does a lot of CPU work. But for I/O, select/poll/etc is usually preferable. It just depends. Node (and Javascript) is definitely missing proper support for threads which is a negative.