A key benefit of the seated cable cuff tricep extension exercise is the stability it provides. Because you have a bench for support, you can keep your shoulder blades locked down. This helps prevent your shoulders from shifting and means you can focus purely on directing tension through the triceps.
Using a cable has the advantage of providing a fairly constant tension throughout the rep meaning it challenges the entire range of motion well.
A unique advantage of this exercise over other triceps extension variations is the use of cuffs rather than a hand-held attachment. When the load is taken out of the hands it is easier to focus on contracting the triceps rather than just moving the weight from A to B.
All too often people tend to fixate on their hands and throwing the weight around. This results in momentum taking over and less work being done by the triceps. By using the cuffs, you aren’t gripping the weight and your focus is able to be fully directed towards the triceps.