node.js does not impose it for everything. Every command in the fs library that has a natural synchronous interpretation (like reading a file, writing a file, ...) has a sync equivalent (readFileSync, writeFileSync, ...)
Sync is great for initialization. Due to the fact you only start up once, you can be as reckless with your performance hindering practices as much as you want as it will never amount to anything more than a few hundred extra milliseconds of startup time.
This is an interesting point. I've found in practice that the speed of server startup times depends on the scale of operations. For example, at a small scale, a 600 ms vs. a 1.2 sec startup makes little difference.
However, at scale such differences can matter. More so when something is going wrong that's causing erratic restarts.
