I agree with you that it’s a core question.
People don’t like it, however, for a whole host of reasons.
I don’t like it either, to be honest - for there the abyss may also stare into you - but I also often find that the things which we don’t like thinking about are critically important things to think about.
I also reach the same conclusion as you: it does not matter. If I cannot discern whether I am responding to a human- or LLM-written response, then we are back to zombie cats in boxes - and therefore the answer as to whether this precious magical spark we call consciousness (which may or may not exist anyway) exists in our interlocutor becomes moot.
And as I say - I may or may not be conscious. I seem to myself to be conscious, based on my understanding of the term - but I cannot prove that what goes on behind my eyes is the same as what goes on behind yours, or even that anything much is going on at all. Perhaps there’s just a narrative layer that likes to use “I” that parasitically explains the universe and the actions of the host to itself, and spreads between hosts through neurolinguistic programming and coadaptation. Maybe that’s what “we” are. I don’t know.
That said, perhaps I am wrong, and that is no small part for me of why this question should be earnestly considered and discussed. How can we possibly seek to understand or define machine intelligence before we examine our own.