It doesn't matter if a bookmarking tool has nested folders, if we only have "TREE STRUCTURE FOLDER" view, then we will end up with a mess once we have dozens of nested folders. Currently if you want to see a nested folder two levels down, you need to see everything else, all the other folders outside of it.
We need an OPTION to switch from "TREE STRUCTURE VIEW" to a "FOCUSED VIEW". It means that we only see the selected folder and its contents - with a “GO ONE LEVEL UP ARROW“.
Like in any computer's browser: they all allow tree structure view OR "focused" view.
Tree structure view is ok if you have 3-4 main folders, and each has 1-2 nested folders. But creative projects and modern life are way more complex than that.
What nobody realises, that the lack of this simple concept is among the main reasons why all bookmarking tools end up as a mess - EVEN if you have nested folders.
But we don't need to reinvent the wheel, just use the good old methods, and allow both tree-structure view and focused view.