> I add things to my reading list as I browse the web and Safari downloads them in the background.
Sure, but PWAs allow for so much more than that. For example, you could not only read the article offline, but also _comment_ on it offline and have your comment automatically posted next time you have a connection. Or you could click a button to have all future articles from a particular news site automatically synced in the background while you're on WiFi so they're available for reading next time you're out; no manual downloading of each individual article required.
> On booking a flight: I'm not sure how doing this offline helps? Last time I did it, I did have to wait for pages to load after clicking links but it was on the order of seconds or less.
A PWA would allow much faster interaction than that. Seconds or less? That's terrible compared to the performance you _could_ be getting out of a PWA (i.e. near instant, like what you'd expect from a native app).
> Doing it offline is not really interesting to me, and I'm not sure how that would work (which is why I'm happy to do it in a browser). Hacker News is more than fast enough. It's really minimal.
Sounds to me like you're already content with the experience you're getting from the web. That's fine, but it's no reason to oppose features that would make the experience even better for those of us who do want them.