Correct on both counts.. Pre-fetching DNS names for origins not on the page is, indeed, a nice use case - redirects are a good example. Similarly, embedding a <link rel=dns-prefetch> in the head will trigger an early DNS lookup, which can, in fact, deliver big latency savings -- you would be surprised how slow DNS lookups are in practice.
Last but not least, AFAIK, I'm not aware of any logic to group DNS-prefetch hints or similar strategies when running over TLS.
I tried implementing it for my blog’s pagination, but I definitely don’t see the zero-second latency Google report in the video, and it doesn’t seem any faster at all.
Can you tell me if it’s actually working from using the pagination at the bottom of the front page, or the pagination inside the permapages: http://pygm.us/1e9KHCYt. (Link fixed.)
Last but not least, AFAIK, I'm not aware of any logic to group DNS-prefetch hints or similar strategies when running over TLS.