The same hash could be used similarly to etags with additional interesting properties. You could, for example, use it to safely retrieve an item that was cached for another website. (E.g. latest JQuery.) Not only it would improve performance, it would make user tracking somewhat more challenging for CDNs, improving privacy.
The potential here is huge, so it's disappointing that these ideas are smudged over multiple unrelated specs, and sometimes missed entirely.
EDIT: sorry - they mention caching and using fallback sources, they don't mention any DHT.
I couldn't find anything that mentions using the hash itself to locate the requested document (in DHT network or in local cache) in that spec. Did I miss it?