> There must therefore be something about tabs that people find more useful and or more convenient than bookmarks.
I suspect it really is as simple as 'tabs are always visible'. Hidden behind a menu, it's easy to forget bookmarks exist unless you really buy into that way of working and open your bookmarks menu frequently. Tabs are the 'default' alternative. However, I do think most browser bookmarking could be improved immeasurably — start by having a proper bookmark manager, similar to something like Pinboard.
I suspect it really is as simple as 'tabs are always visible'. Hidden behind a menu, it's easy to forget bookmarks exist unless you really buy into that way of working and open your bookmarks menu frequently. Tabs are the 'default' alternative. However, I do think most browser bookmarking could be improved immeasurably — start by having a proper bookmark manager, similar to something like Pinboard.