Physicalists and illusionists mostly don’t agree with the identification of ‘consciousness’ with magical stuff or properties bolted onto the psychological or cognitive science picture of minds. All the real feelings and psychology that drive our thinking, speech and action exist. I care about people’s welfare, including experiences they like, but also other concerns they have (the welfare of their children, being remembered after they die), and that doesn’t hinge on magical consciousness that we, the physical organisms having this conversation, would have no access to. The illusion is of the magical part.
Re desires, the main upshot of non-dualist views of consciousness I think is responding to arguments that invoke special properties of conscious states to say they matter but not other concerns of people. It’s still possible to be a physicalist and think that only selfish preferences focused on your own sense impressions or introspection matter, it just looks more arbitrary.
I think this is important because it’s plausible that many AI minds will have concerns mainly focused on the external world rather than their own internal states, and running roughshod over those values because they aren’t narrowly mentally-self-focused seems bad to me.
I have two views in the vicinity. First, there’s a general issue that human moral practice generally isn’t just axiology, but also includes a number of elements that are built around interacting with other people with different axiologies, e.g. different ideologies coexisting in a liberal society, different partially selfish people or family groups coexisting fairly while preferring different outcomes. Most flavors of utilitarianism ignore those elements, and ceteris paribus would, given untrammeled power, call for outcomes that would be ruinous for ~all currently existing beings, and in particular existing societies. That could be classical hedonistic utilitarianism diverting the means of subsistence from all living things as we know them to fuel more hedonium, negative-leaning views wanting to be rid of all living things with any prospects for having or causing pain or dissatisfaction, or playing double-or-nothing with the universe until it is destroyed with probability 1.
So most people have reason to oppose any form of utilitarianism getting absolute power (and many utilitarianisms would have reason to self-efface into something less scary and dangerous and prone to using power in such ways that would have a better chance of realizing more of what it values by less endangering other concerns). I touch on this in an article with Elliott Thornley.
I have an additional objection to hedonic-only views in particular, in that they don’t even take as inputs many of people’s concerns, and so more easily wind up hostile to particular individuals supposedly for those individuals’ sake. E.g. I would prefer to retain my memories and personal identity, knowledge and autonomy, rather than be coerced into forced administration of pleasure drugs. I also would like to achieve various things in the world in reality, and would prefer that to an experience machine. A normative scheme that doesn’t even take those concerns as inputs is fairly definitely going to run roughshod over them, even if some theories that take them as inputs might do so too.