This is the same logic that I used when I was at Flock to convince them to do away with folders in bookmarks... of course, since I left, they've added back the folders owning to long-in-the-tooth Firefox users. Ironically, Flock was perfectly suited for this change since no social bookmarking service (besides Shadows) allows folders for storing bookmarks. You'd think that that constraint alone would have prevented them from adding back that UI relic.