I'm undecided about whether the Semantic Web is generally useful for not, but in certain domains it does seem to have some worth.

When building a public scientific database I really want the URL identifying the item in the database to return the page for that item when I enter it in a browser but to return the appropriately structured data for that item when requested with "Accept: application/ld+json" or "application/rdf+xml" by a linked data library.

So it's unfortunate that there's no good way to support this with common CDNs.

Of course I always make it so that appending "?type=json" or "?type=xml" gets you the appropriate document.