Why Are Gun Buybacks Still a Thing?

So gun buybacks are a thing that serious Democratic candidates are now discussing. I'm trying really hard to take it seriously but it seems like just wild pandering and misguided bloviating. Reason wrote up a post about how exactly would a gun buyback actually work work:

We don't have to look to New Zealand's recent flop of a mandatory buyback, where less than 10 percent of the country's estimated number of newly banned weapons have been handed over  so far, to answer those questions. There's a great case study right here in the bluest of blue states: New York.

Gov. Andrew Cuomo hailed the 2013 New York SAFE Act as the toughest gun control law in the nation, and one of its most important provisions was the mandatory registration of all "assault weapons" in the state. This isn't a confiscation or even a ban, so it's nowhere near as severe as what O'Rourke and others are pushing—it's just a teeny weeny little registration requirement.

So how has that worked out? Well, according to the National Shooting Sports Foundation's conservative estimate, New Yorkers owned about 1 million "assault weapons" at the time the ban was passed. So the 44,000 that were actually registered are about 4 percent of the total. This noncompliance with the law is widespread and mostly open, but the police aren't doing much about it.

There's a few other issues that I'm just glossing over but I really want to know whether people are seriously really legitimately asking for for a gun buyback because it totally seems either incredibly dangerous or wildly ineffective.

For one, it appears that the focus on "assault weapons" is a convenient scapegoat even though the overwhelming majority of firearm homicides are by handguns. Why not commit to a mandatory handgun buyback? Especially since common semi-automatic models are made to accept 100-round magazines.

Second, for many years gun owners have heard the refrain of "No one is coming for your guns" and that has now evaporated into mist. People really fucking like their guns. If a bunch of cattle ranchers took over a government building to protest grazing fee enforcement, I can't fucking imagine the shit they'll pull when you tell them they have to surrender their firearms.

How exactly would this be enforced? Technically there is no gun registry (The ATF does operate a deliberately handicapped tracing facility in WV where computers are banned) so there's no real way of knowing who actually owns guns. Even if you did, how do you deal with folks who refuse to participate in the 'mandatory' buyback? I assume the only recourse is to send armed men to arrest them which...does not seem like a good idea given the situation.

I'm ignoring for now the legality of such a proposal, the baffling focus on irrelevant firearm features, and the prominence of 3d printing and 80% lowers. The list kind of goes on. From where I'm sitting, it doesn't seem like the advocates have actually thought through beyond step 1. I'm open to changing my mind if there is evidence.