I'm tired of these stories about Robinson Crusoe and the value he gives to things he finds on his island.
Money, not just bitcoin, not just gold, is pretty much useless when you're alone. Lots of things are useless when you're alone. Basically, communication tools. Had Robinson Crusoe found a mobile phone, it would be the same (assuming he has no network, of course). A phone is useless if you can't call anyone nor receive calls.
And yet, has anyone ever claimed that a mobile phone has no intrinsic value?