1,706 votesFarrell, Sean J commented
With several accounts, or with an account using multiple folders the "smart folders" section disappears off the bottom of the sidebar. With the ability to add 'smart folders' to favorite, it would give capability for power users to create their customised search folders, and to bring them to the top for quick access and frequent use.
372 votesFarrell, Sean J commented
Either capability to reposition the Smart Folder, or to "Allow smart folders to be added to Favorites" would give similar capability: