Potentially almost all of it, but the point is that if _most_ of your requirements are "get thing, do thing with it, decide other thing to do based on that" you don't have to spin off three goroutines to accomplish it (roughly the equivalent, as far as wasted effort/mental overhead goes, of needless promises/callbacks which are abused to work out identically to performing those things in sequence). You do it all in one. Maybe it's just me, but I find that most of the time what I need to do can be boiled down to between 1 and 3 (and usually on the lower end of that) lists of things that need to be done in sequence (threads, if you will) and that Node is a poor fit for that, since its ideal case seems to be doing dozens of things, none of which depend on one another, then collecting them at the end, which is something I rarely ever need to do—if I do, typically the the "dozens of things" are really just one or two things with different data and therefore are very easy to parallelize without resorting to Node's typical patterns.

I'm sure there's a workload where async-all-the-things makes things easier rather than harder, I just haven't run into it.

[EDIT] "rarely never" to the intended "rarely ever"