A lot of the edge cases like back pressure and certain kinds of state machines are a lot easier to represent as function calls rather than an asynchronous events. Most of the good implementations of these ideas with events have some sort of manually managed stack-equivalent device, which is exactly what a green thread already is.<p>So from there the benefits are around being able to use the sequential features of the language in combination (error handling, flow control, &amp;c). Stackless transformations are a middle ground but there are plenty of things that become inconvenient without green thread stacks which make composition much easier.