Tab completion with these settings takes some extra keystrokes: if there's only one match, you have to press tab twice to see what's in the subfolder. If you have several matches, you have to press tab, then enter to select the one you want, and then tab again to show the subfolder contents. And going up (especially several) folders is also quite a bit of typing. It might sound like splitting hairs to shave off less than five keystrokes, but it really does make a difference in how smooth the browsing feels.