The concept is old. The technology that appears to give a smart gun the chance of actually working the way they claim it will is still to new to evaluate with any certainty, beyond the obvious "it ain't got the bugs out yet".
The anti gun bigots want it to work, and will happily make "smart guns" one of their main talking points, as soon as some smart gun, somewhere actually does work.
And they won't care if it only works 10 times out of a hundred. THey will sieze on it, fixate on it, and tell all of us, over and over, and over how the smart gun is the only "safe" gun, and ALL other guns must be turned in!
The fact that the smart gun tech also allows for some kind of master override, won't be mentioned by them, and if we bring it up, its just a "paranoid fantasy".