Well, S&W really did seem to try the KISS principle. Taurus's "lock" involves multiple turns of a screw; Ruger's involves removal of the grips. Both seem to take the (probably correct) view that most buyers will never use the lock and that (as Fuff says) it is mainly to cover the manufacturer's fanny and put the burden on the gun owner for any accident. S&W seems to really have the idea that if the lock were easy to use it would be used. Their design seems to have (or have had) problems, but it is easier to use than the other brands. Of course a plain old padlock would be as easy to use as any but would not satisfy the anti-gun gang whose idea is to make guns more expensive and harder to use, lest someone shoot a crook who is paying off the mayor.
Jim
Jim