Simon Tatham is a huge fan of coroutines and has been since the mid-1990s when he first encountered the idea while reading The Art of Computer Programming. He found coroutines to be a game changer and even developed a way to use them in C code. He believes coroutines are incredibly useful compared to explicit state machines and conventional threads because they allow for clearer code structure. While multithreading is an alternative to coroutines, Tatham prefers the single-threaded approach for simplicity and easier debugging. He is optimistic about coroutines becoming more mainstream and is pleased to see support for them in various programming languages.
https://www.chiark.greenend.org.uk/~sgtatham/quasiblog/coroutines-philosophy/