The Adwaita folder icons look more practical than Suru folder icons. No practical folder in any office/home have curved corners. A folder with curved corners cannot be opened correctly. The documents you put in a folder are rectangles with 90 degree corners. (Stationary store) The documents/papers are kept vertically in a folder. So, any folder icon with 90 degree bottom corners would look practical. So, Ubuntu Mono icons (Humanity) folder icons are more practical than Suru folder icons.