That doesn't mean it isn't useful, for example for a search engine for an internal wiki where you don't have to worry about SEO or spam. And you said yourself g

That doesn't mean it isn't useful, for example for a search engine for an internal wiki where you don't have to worry about SEO or spam. And you said yourself google still uses it, so it would probably still be useful to other search engines, including niche search engines, just not as the only ranking mechanism.