An article in Forbes covers many of the bases that you and I have over the past few years here. However, the author introduces some new objections:

6. Smartguns might be hackable! Even without embedded tracking or jamming technology, smart guns that rely on radio-frequency (i.e., wireless) transmissions – like the aforementioned gun-watch pair, for example – might be susceptible to remote jamming – not something that a law enforcement officer or law-abiding citizen would want to find out when a thug is threatening her with a weapon equipped with a jammer atop. Governments might gain the ability to disable people’s private weapons, and criminals might gain the ability to do so to police service weapons.

[ . . . ]

10. Firearms must be able to be disassembled in order to be cleaned and maintained. One of the principles of information security is that someone who has physical access to a machine can undermine its security. Smartgun manufacturers need to show evidence that criminals who steal smartguns cannot modify them to work with the smart technology removed or disabled (or that preventing any components from being accessed that are accessible in conventional weapons will not impact the durability of the weapons).

More at the link.

Related: From Politico a few months ago:

Sen. Ed Markey of Massachusetts plans to introduce a bill that would require new handguns be outfitted with personalization technology within two years and that older guns be retrofitted within three years so that the firearms won’t work for unauthorized users. The bill includes exemptions for antique guns as well as military arms.