You can use these surfaces in your part modeling or even to manufacture them using the 3D techniques, or to modify with the Surface editing tools so you can join your 2.5D features to your 3D features.
Features can be a shortcut to create swept and cap surfaces with the familiar dimension driven feature interface. The draft angle, or radiused features produce a swept surface for the side walls (including chamfer and bottom/top radius) and a cap surface for the bottom in one operation.