How good is Zotero as a bookmark manager similar to Pinboard.in or Raindrop.io? Both have a paid feature that stores a permanent copy of a site, but these are stored only on their servers, and Pinboard's archive download feature never worked for me.
Zotero uses SingleFile. (Side note, this is, as far as I know, a destructive process—you can't recover the original bits. It would be interesting if Zotero switched to SingleFileZ and there were a sidecar file embedded in the ZIP container that would let you reverse the transformations to get the originals back out—or just store them directly.)
Zotero's snapshots work well enough on most pages you'd care to throw at it in an academic context. Your mileage may vary if you're using it as a general bookmarks manager, owing to the amount of client-side scripting-driven chicanery on the Web today. Notable example that I've found that Zotero didn't handle well at one point: Medium (although the data was there―the saved copy just wouldn't render correctly in-browser when opened; this doesn't appear to be an issue anymore for new snapshots, at least for now).
For most stuff that I want to have a durable URL for but that I feel doesn't merit being in my Zotero library, I just use ordinary browser bookmarks and make sure that the Wayback Machine and/or archive.is has a copy.
I've used Zotero for over a decade to save webpages. It works fine in my experience, though I'd prefer if Zotero saved all the assets in a single file.
