My intuition is that consciousness, as an a priori concept, is not useful. Like the four humours in the medical world, it's a metaphor that captures just enough truth to be a blunt instrument. However it's a local maxima. And a honeypot in the neuroscience domain.

So much effort is spent trying to pin down a definition of consciousness. Ask five people and you'll get five definitions. And yet everyone is so sure they know who has it and who doesn't. Slugs don't have it, dogs don't have it, maybe elephants do? Apparently they can talk to each other and mourn the dead.

One possible motive behind humanity's fascination with consciousness, and our speed at assigning or withholding it, is that it gatekeeps the belief in an anthropocentric universe. The human experience is the one we understand, and if you don't have it you are not conscious. Consciousness then, is a Turing test for how passibly human you are. Slugs could get some of the consciousness table scraps if they'd only mourn their dead.

As we learn more about other species; and coming from the other end too as computers (big data really) reveal new sightlines on human determinism; consciousness as a metaphor is strained and loses adherence.