A magazine disconnect is not a substitute for properly storing an unloaded, unattended gun where it is not accessible to unauthorized people.
And what pray tell IS the proper method for storing an unattended, unloaded gun where its not accessable?
A gun lockbox? How hilarious. A young kid with a brain and time can locate and open those easily enough. A burglar can do it faster, since they don't have to take the time to cover their tracks.
A gun safe? You solve the kid access problem, but now you can't get to them either. When Joe Felony breaks in he's not going to hang out in the living room while you run to the closet and punch in a combination.
A magazine disconnect is not a substitute for proper gun handling skills or training, but it serves as a passive feature which can be used to deactivate a handgun when its not in immediate need, while simultaneously allowing for a chambered state which only requires insertion of an easily controlled magazine to 'activate'.
For most of us non-Special Operations people, 94.98% of the time the gun isn't remotely likely to be used. A mag disconnect ensures that when Junior-or his girlfriend you don't know about- finds the piece the worst outcome is harsh words and a boot in the rear, instead of a loud bang followed by a dead body and police attention.
Amazing how people become bent out of shape regarding a feature which has saved lives. Its akin to someone despising airbags in a car.