Value is in the eye of the beholder and is completely subjective. My point about cost to make is that it is not creating something from nothing like fiat currency which is faith based. Nagle can redeem his Federal Reserve Notes for lawful money and then we can talk. He knows he can't even though it is Federal Law. They are the biggest scam ever. You have no legal recourse for non-payment within the US.
As far as meaningless bits... how meaningless is ink formed in the shape of 100 versus 1? The ink is no more valuable . Whereas 100 bitcoins versus 1 bitcoins means the network is that more secure and the transaction (regardless of what 2 people choose to make them represent) that much more real.
They're both equally meaningless - one is given value by decree, that you can use it to buy a shit-ton of things all across the country. The other is given value primarily through speculation, but also a miniscule but steadily growing market of things you can buy with it also. Without that steadily growing list of things you can actually buy directly with it, the only value it has is in your ability to find a greater fool to pass it on to.
Look at it another way - what do you think would happen to the USD if everyone outside the US's legal jurisdiction suddenly decided they didn't want to accept USD anymore? Even discounting the fact we'd still have a domestic market for them, there would suddenly by a whole load of people on the planet wanting to get rid of them in exchange for something more useful to them. Bitcoin's value is kind of like that, except you don't have the most powerful armed force in the world forcing you to use it.