When I press CTRL+SHIFT+O there is a "Tags" object containing all of my tags on the left. I want to use this as a folder on my bookmarks toolbar, so I can easily browse all bookmarks with the specific tag.
In the Bookmarks menu there is a "Recent tags" folder, but this does not contain all of my tags.
It think that keeping bookmarks in their folders AND tag them, but able to browse them by their tag(s) name(s) makes sense not only for the "Unsorted bookmarks" type (which aren't moved to a specific folder).
One bookmark can have several tags and a tag can belong to several bookmarked pages, no exception here from either point of view.