@1:10:20

With HTML you have, broadly speaking, an experience and you have content and CSS and a browser and a server and it all comes together at a particular moment in time, and the end user sitting at a desktop or holding their phone they get to see something. That includes dynamic content, or an ad was served, or whatever it is—it's an experience. PDF on the otherhand is a record. It persists, and I can share it with you. I can deliver it to you [...]

NB: I agree with the distinction being made here, but I disagree that the former description is inherent to HTML. It's not inherent to anything, really, so much as it is emergent—the result of people acting as if they're dealing in live systems when they shouldn't.