Save As Copy...
Different from "save as..." as "save as copy..." would allow you to keep working on your current file, while creating a new file with the current state of your work.
Would be great on those random but creative circumstances where you unexpectedly find something very cool for a node idea, but it doesn't fit your objective. You want to save it for later exploration but you have real work to fulfil so, as you don't want to ditch it away what you do is "save as..." into a new folder and then "save as..." again into the previous working file. "Save As Copy"... would streamline this action allowing you to focus on current work.
Always need something like this. +1