A magazine disconnect in practical use has little to do with administrative gun handling. A moron negligent enough to mishandle a firearm won't be deterred by any safety.

Rather, a MD was included based on S&W's research with the Illinois State Police who adopted the original Model 39s back in the day as service pistols.A number of their troopers are alive today because when the crook got their duty weapons the troopers ejected the mags and prevented the bad guy from killing them. Remember in Law Enforcement police have to be in conversation distance from suspect to gather information and determine details about crimes and incidents. The Tuller Drill establishes that a man with a knife at 21 feet away is a threat, and LE routinely operates at conversation distances.That close anyone can grab a duty weapon before the LEO knows what to do, and that MD can mean the difference between survival and being shot with one's own weapon.

As far as civilian use goes the MD has more of a use when a citizen needs to disable a weapon on the fly. Say one has to visit a "no carry" zone like a post office or hospital. Barring metal detectors or other safety concerns with carrying loaded magazines, eject the mag and take it with you. If a crook steals the vehicle they don't get a functional firearm in the process. Come back to car, stick mag back in and go on with the day.

Staying the night at a friends place ,and said friend has kids but no gun safe or secure storage apparatus? No problem. With an MD equipped weapon all the owner need do is eject and maintain control of the magazine. Should trouble come knocking once the mag is in the gun its ready to go.