>Why would you want hundreds of full page renderings open on your computer at one time while you're doing other things?For me, it's not hundreds. It's usually less than 50.
For throwaway content (not elevated to reference), the active tabs are easier to get to than navigating the bookmarks UI.
>Would a screenshot being saved with your bookmark solve this need?
It might help in some aspects but the core problem remains: the bookmarks UI is a separate area that I don't want to "manage" and that effort isn't worth it unless the webpage is promoted to reference status. Dozens of open tabs are just way easier and a more seamless experience. I often cycle through open tabs with Ctrl+PgUp and Ctrl+PgDn similar to cycling through active windows with Alt-Tab. Bookmarks UI don't have a "cycle" mode.