That still requires you to deliberately decide to archive a certain page, which you can do just as easily with http. The SingleFile browser extension will grab everything that's linked to a page and build a locally stored directory with all the dependencies of that page.
> That still requires you to deliberately decide to archive a certain page
You don't "archive" a page with IPFS, with IPFS everything you keep a copy of stays available under the same address, that either happens automatically via cache or via a manual 'pin'. That's fundamentally different than what HTTP does.
The archive copy you create of a HTTP site is your own personal copy and completely inaccessible to anybody else. Even if you put it online, people would have no clue where to find it. With IPFS the document never leaves the address space and stays accessible to everybody under the same address, no matter who decides to host it.
Another important practical difference is that IPFS has native support for directories, so you don't have to try to spider around to try to guess all the URLs, you can just grab the whole directory at once. That in turn also has the nice side effect that .zip archives essentially become irrelevant, as you can just upload the directory itself.