> You're not really transferring Bitcoin though, you're just adjusting a ledger of who owns what.
If not this, what do you think a Bitcoin transfer looks like?
> There's nothing stopping you from doing the same thing with some gold
The custodian of the gold would be able to steal it from me at any time. I wouldn't actually be in possession of the gold, whereas I would be in possession of my Bitcoin keys.
The point is that physically sending the gold is not the equivalent sense of the word transfer in this case. There will of course be some differences, but the gold ledger is the best gold analog of a bitcoin transaction.
The question is a matter of trust in the correctness of any such ledger.
Bitcoin only exists as entries in a trustless ledger. The trustless ledger of gold is physical possession of that gold -- that's the only way that you can verify possession (or spend freely) without a mutually trusted third party.
If not this, what do you think a Bitcoin transfer looks like?
> There's nothing stopping you from doing the same thing with some gold
The custodian of the gold would be able to steal it from me at any time. I wouldn't actually be in possession of the gold, whereas I would be in possession of my Bitcoin keys.