Just suppose that smart guns were safer than ordinary guns.
For example, if someone grabbed your gun and tried to point it at you. If it was a smart gun you'd be perfectly safe because there is a fool-proof mechanism that prevents its use by an unauthorized person.
As with any technological advance, some people are sceptical. How much do you trust new technology? Suppose the gun doesn't work when you need it. Maybe an electromagnetic pulse (triggered by terrorists or natural solar activity) might take out all weapons in the area. Or maybe the bad guys (or the FBI) can hack into this mechanism and disable your gun before they attack you.
Meanwhile, like many technological advances, there are political implications. In the USA, the key question is whether such a mechanism might help reduce gun violence. Some gun control activists think such a mechanism would be pretty irrelevant.
But that doesn't stop the gun rights activists freaking out at the prospect of any damn technology on their precious weaponry. A shop owner in the US claims to have received death threats from pro-gun lobbyists for offering to sell the weapons. Meanwhile, as Joseph Steinberg suggests, an obsession with smart guns
may inhibit other technological innovations that could make guns and
Because once these smart guns are available, by a process of technological determinism, they become irresistible to legislators. Before long, you won't be able to buy regular guns.
Obviously that's a cause worth killing for.
David Kopel, Brady Center lawsuit to use “smart” gun mandate to trigger handgun ban in New Jersey (Washington Post 22 May 2014)
Karen McVeigh, Gun control groups accuse New Jersey of ignoring 'smart gun' law (Guardian 21 May 2014)
Michael S. Rosenwald, Maryland dealer, under pressure from gun-rights activists, drops plan to sell smart gun (Washington Post, 1 May 2014)
Joseph Steinberg, Why You Should Be Concerned About The New 'Smart Guns' (Whether You Love Or Hate Guns) (Forbes 4 May 2014)
Nicholas Tufnell, Smart guns: How smart are they? (BBC News, 23 May 2014)
Eugene Volokh, Smart guns, electromagnetic pulse, and planning for unknown-probability dangers (Washington Post 23 May 2014)
See also Batman/Catwoman: Trail of the Gun (hat tip @ChBrain).