Well I don't know about most people but to speak for myself I mostly write high performance network servers, databases and queues and in my world concurrency (if not parallelism) is strictly necessary. For me it's also not a recent development or a fad, it's been this way my entire ~15ish year career.

I imagine folks writing Web software, UIs and heavy desktop applications will also benefit from these developments but those areas are out of my core expertise so I can't speak to exactly how useful structured concurrency will be for them however I can see very clear applications for my domain.