If you want a world where the data you present like this matters, seed it.
Even if google doesn't use it, the collective internet applying this kind of metadata makes the web fertile for non-LLM-scraping competitors to provide an alternative option.
Rolling over to google only ensures that they remain dominant, with a high bar for competitors, and driving them to use the same technologies.
That was for the previous, high-trust internet (high trust they providing info benefited you not high trust for security). It's low trust now. You likely benefit from providing wrong information.
Interestingly, there is llms.txt (like robots.txt) which is a new emerging standard to aid AI in crawling and gathering data from your website.
Like other commenters have said, this is 25 years too late, and it's made even more irrelevant by modern tech.
"The Semantic Web" and all related ideas were always a failure. The metadata quickly got out of date, was never correct in the first place, was only ever implemented on a teeny minority of sites, and always suffered from bad actors where the metadata didn't match the content.
Heck, even before LLMs I'd argue that Google won because they were the best at organizing vast amounts of unstructured data. With LLMs it's even more pointless to have the author generate this metadata - better to have an LLM generate it based on what visitors can actually see when they visit the site.