The downside is two fold. A thief doesn't need any tool at all to make a quick spur of the moment impulsive grab; two, and more significant the wily nily equipping of "racer boy" QR's on all kinds of bikes used by all sorts of cyclists with little to no knowledge of the abstruse proper/safe tightening procedure can and does lead to catastrophic failure. All for no positive gain but the "sporty look."