Well, you're human, so I don't think you can really have concerns about what happens a billion years from now because you can't imagine that period of time.

I can't imagine the difference between sixteen million dollars and ten million dollars - in my imagination, the stuff I do with the money is exactly the same. I definitely prefer 16 to 10 though. In much the same way, my imagination of a million dollars and a billion dollars doesn't differ too much; I would also prefer the billion. I don't know if I need to imagine a billion years accurately in order to prefer it, or have concerns about it becoming less likely.