Having some "feature" that means the concurrency model is sound (aka without undefined behaviour) isn't irrelevant to concurrency models. (I quoted feature beca

Having some "feature" that means the concurrency model is sound (aka without undefined behaviour) isn't irrelevant to concurrency models. (I quoted feature because there's a variety of different ways to get this guarantee, some of which don't feel like language features, per se.) On the other hand, it's fair that the convention/tooling is usually good enough; this is a stronger argument and probably a better one to be making than a dubious one about being irrelevant.