Aside from the fact that the technology doesn't exist... What if I want to let a friend shoot my gun, for example when I was teaching someone to shoot? What if I wanted to try a friend's gun so I could see if I liked it? How about collectible guns? The last firearm I bought was a WWII vintage Finnish rifle. What if I wanted to buy a very-collectable WWII 1911? Would that be legal? It's just another blatant attempt to restrict my constitutional rights. If you want to pass gun control, amend the Constitution. Stop wasting our time with this kind of legislative theater.
All guns should be retrofitted with the biometric checks. That black powder musket must how have a $200 electronic device bolted to it or else you're a mass-murderer. Trying to let a friend use a gun? Nuh uh, you must transfer the gun at an FFL so your friend gets background checked, mental health history checked, political affiliations checked, and a credit check. When he returns it, you must transfer it back to yourself to make sure you didn't become a criminal within that 30 minute period or develop a nervous tick or become an alcoholic.
Anything short of that and you want to murder children.