[f_devd]

This misses the actual async part, which is more like polling a task queue. Callback hell sugar is only a thing in langues that already have event loops built in (i.e. JavaScript, which I assume is also what you're referring to)

[jayd16]

The point is that it actually is insightful to think of it as callback sugar. That will give you better understanding of how the threading is handled when the calling method yields to the callee and conversely how it must be different when the caller isn't yielded.

[Matthias247]

It generally applies to eventloops, not just to lanugages with a builtin event loop. E.g. it certainly also applies to raw boost::asio which uses callbacks, libuv, libevent, QT, GObject, Netty, etc.