SEO was always a good argument to adopt some of the microformats. Search engines can make use of that to pick apart content. It's just that we have a few more t

SEO was always a good argument to adopt some of the microformats. Search engines can make use of that to pick apart content. It's just that we have a few more tools than just microformats for that now; including some structural html 5 tags. What died out is attempts to do stuff with microformats via browser extensions. This was once a thing that e.g. MS did when they launched Edge. Those extensions have largely disappeared or just never really caught on.