I think that biometric & other electronic methods (such as a chip in the gun that has to in certain proximity to a chip in your watch to fire) are a great idea, but they need to be absolutely foolproof before widespread deployment. It's a great idea for cops especially, who have an alarmingly high chance of their own firearm being used against them.

It also protects the civilian gun owner, as a stolen firearm would be largely worthless. Though I'm sure a smart enough thief could disable any electronic lockout given enough time.