Quickstops are definitely not just a military manoeuvre. I'm quite surprised if they aren't in the PPL syllabus; I would see them as a normal way to fly a helicopter, especially a small one.
For example, they are useful for safely "expediting" an exit from a runway when being chased down the approach by a fixed wing aircraft. Also any situation where it's useful to operate close to the ground, such as a rapid move from one side of the airfield to the other (obviously, not in the avoid curve), rather than flying a full circuit.