Right, as a physicalist I'd agree with the line of reasoning that an atom-for-atom identical configuration should have identical experiences, including subjecti

Right, as a physicalist I'd agree with the line of reasoning that an atom-for-atom identical configuration should have identical experiences, including subjective qualia (or, if we build an atom-for-atom exact copy, it would honestly report no qualia if they are produced by some dualist "soul" or other non-physicalist-explanation that is missing in our copy). I think the p-zombie thought experiment is useful as an intuition pump in a few ways though; the other is to consider what would be the "most similar" thing to us that doesn't have qualia. Sure, it's not an atom-by-atom identical thing. But what if we do a sort of "Chinese room" scenario and train an AI to perfectly replicate a human mind, situated in a human body? Currently, AIs are trained to predict/complete human utterances, and to do this task well requires a sophisticated theory of mind. Possibly, to do it perfectly requires (a simulation of) full consciousness, we’ll see. But if we train an AI to predict human utterances it will say things like “I feel pleasure when X” or “Y produces a subjective experience of red”, since those utterances are in the training set. And yet, this AI might not actually have qualia. (Indeed this is the default explanation for an AI's behaviors/utterances.) We can also consider a sort of Ship of Theseus argument here too; if we modify a mind-body atom-by-atom, what's the shortest edit path to a mind that does not have qualia? Or, in the other direction, what's the edit path from the above qualia-less AI to one with qualia? So I think Eleizer's argument is sound that an atom-for-atom copy ("neurological zombie" I believe is the strict term when disambiguating zombie types) would not report qualia. But the concept-space is still useful, if we consider the adjacent "dishonest AI zombies" AKA "behavioral zombies" (noting that "neurological zombies" are but one formulation of the p-zombie concept used by philosophers over the years, albeit the best-known). It seems clear to me that in humans, outward behavior is causally influenced by the experience of qualia. But there are potentially other (dishonest/deceptive) mind-constructions that could produce the same behavior without qualia. Probably not parsimoniously though!