You can bookmark more than just pages that are live on the World Wide Web.
I also expect offline access would be useful if you can reach the Web but can't reach Delicious.
but no news on delicious.com
Found it on:
but since August, 2015 it did not show new links.
A bit late, but ..
I, myself, have finally had it with there being no replacement for the "really delicious" addon from the old days you speak of. Not only has the old addon that I have kept running finally gone to a state of too many bugs, after days of searching I didn't find anything close to what was offered by it before (on any browser!).
So, I think ...