The detachable upper bout option is attached with two allen screws and can be easily removed. The upper bout is intended to accurately simulate the feel of the rib and edges of an acoustic violin and is used to help players with classical training find their upper positions more accurately.
Many players with extensive classical training find it liberating to not have their hand run into the body in upper position playing and choose not to select the upper bout as an option, finding that the freedom of movement allows for new techniques. Most traditional fiddlers and players in other styles of music do not select the upper bout as an option, but there are exceptions.
If a player is uncertain as to whether or not they need an upper bout I often suggest that they try playing without one for a while. Then if they find it difficult to play in tune in upper positions, they can have one added later. The Jordan detachable upper bout is unique in that it accurately simulates the feel of the rib and the top and back edges of the violin, this gives a more accurate sense of correct position than the minimal theaded in wires and other minimal bouts offered by most other makers.