I tend to think consciousness is probably something we subjectively assign importance to, but doesn't really describe anything meaningful.
I personally suspect consciousness is just a side-effect of empathy because it's very hard to empathise for mechanical "unconscious" agents. Therefore it benefits us all to have an illusion consciousness, otherwise why would I care if you're in pain, or for your feelings? And we see attitude manifest with psychopaths. Wood is on fire vs human is on fire is only different in our minds because of our perception of consciousness, and without consciousness your care would probably be more utility based.
So perhaps it matters if we don't want computers to treat us like the machines we are, but I think it's possible there are other ways to achieve empathy without an illusion of consciousness.
That's just my take though. I don't think consciousness really matters for AGI and like you say, there's really no way we'd know if a computer is conscious anyway. I'd actually side on it not being conscious if a computer claimed to be. I tend to think the best indicator of consciousness wouldn't be the claim of it, but acting irrationally. I feel confident people around me are conscious, not because they tell me they are, but because I've seen them do objectively stupid things which are explainable by irrational conscious feelings like fear or pride.