Yet Bitcoin can do things Gold cannot. It can be send instantly across the world, it can be stored safer than Gold (by individuals) and there is not an unlimited supply of it. I see this as Gold v2.0
Gold can still do a few things bitcoin cannot. It can be traded in person, anytime, anywhere, without electronics, during an EMP strike, during an internet outage, during a power outage, during a zombie apocalypse. It is a little easier to verify a gold coin than a casascius coin (you can't bite on, weigh & measure a casascius to determine whether its private key is valid.)
Note that
I totally agree that bitcoin is better than gold in too many ways to count and is the "currency of the future blah blah blah" etc etc. But let's not forget that gold is gold and bitcoin is bitcoin.
As for whether they are coupled - physical gold price is currently coupled to paper gold price, and both are being manipulated. There are oodles of manipulation in the world of PMs. PMs will stop being manipulated well after the Bitcoin train has left the station, and by then, they might only be used in appalachian backwater regions by people who shun technology, or kept as a store of value.
I see all these ridiculous arguments in gold threads here "in a zombie apocalypse, weapons and potable water is more valuable than gold." Let me just point to the numerous examples of countries whose citizens have started using gold & silver - not primarily, but still a use case - during times of hyperinflation and other crises. Please get it into y'alls head that your "zombie apocalypse" is not the only disaster scenario that could ever possibly happen in all of time.
In this bizarro-world of the bitcoin-fanboi/gold-h8r, everything is either (1) peachy clean and every single person on the earth has a computer with bitcoind running, or (2) zombie apocalypse where no currency matters, you just need guns and rice and water to survive. Guess what? We're in between those two scenarios right now... and probably will be forever. So, gold is gold and bitcoin is bitcoin.