I'll agree that the best place is holstered on the person.
But its just a fact there are times ,such as entering a school or post office,that its not OK to carry.
Its good to have a secure storage option in the vehicle.
That's a STORAGE option.,not a carry option.If you have time to unlock the box in a crisis,,you have time to leave and call 911..
The vehicle attached holster...may have potential,depending on circumstance.
Not all folks can carry appendix,and many holsters are not accessible when belted in a seat.Folks do have ND's unholstering or reholstering 3 or 4 oclock concealed carry while in a car.IMO,it should be a retention holster.
As far as the hazards of any holstering/unholstering...I guess you have to know your own limitations.If you feel you might muzzle sweep people,Thats your call and something to think about.
If the gun is in a door pocket,it still needs a holster.A pencil or tire gauge can enter the trigger guard.
I forget all the details,but in the famous FBI/bank robber shootout,an issue was the FBI guns were on the seat.Whether it was vigorous braking or collision,I don't remember,but the guns went flying to the floor.That wasa factor in the debacle.
Have a wreck or a rollover,you don't wasn't 2 1/2 pounds of cocked and locked flying around the vehicle.
IMO,it IS absolutely unacceptable to have an accessible firearm in a car with kids unattended.However,IMO,its absolutely unacceptable to have unattended kids in a car,period. Even to just run in to 7-11.
In summary,should a lockbox be "Plan A" for being armed? Not IMO. Its as easy to drive away from trouble.Ideally,both you and your wife are trained,armed,and practice.,and carry on your person.A team of two is far superior.
But is a lockbox a good plan for " I really need to temporarily disarm.What do I do with my gun?" IMO,its a very good accessory.