It’s actually fairly rare that you get to choose what language and language features are used in the code base that you’re responsible for. Sure, if you’re the tech lead at a startup, or working on a personal project, but for all my day jobs, I’ve not once gotten to choose anything that fundamental about the code base.

So just in general, I do think it’s fair criticism of a language for offering crappy features, even if it is “optional” to use them. (Not arguing either way for coroutines specifically, as I’m not a c++ dev).