Advantages of gold over bitcoin:
If there's a total internet && computer && electricity apocalypse, a physical barter exchange with gold is more trustless than bitcoin. You can still transact bitcoin but there's trust involved.
Advantages of Bitcoin over gold:
No trusted third party (If you're moving sizable sums of gold, you're doing it with a trusted third party[TTP))
99.99226%[1] transaction uptime (Your TTP keep business hours)
No countries win the gold-geography lottery (Your country that has no gold reserves can still accumulate)
Instantly assay the value (gold takes time)
You can use latent renewable energy to mine bitcoin (the way that miners remain profitable is by using cheap hydro power that would be wasted if not consumed) No need to blow up mountains to sift for gold.
Bitcoin is programmable value (People in places without functioning judicial/commercial systems can create contracts with each other)
You cannot practically bring more bitcoin to market if the price increases (The price of gold dictates which gold fields are profitable to produce)
Most importantly, it separates money that citizens use and the onus of financial obligations that the oligopoly (Banker's bailout 2008) and political class (Endless war) place on citizens.
[1]http://bitcoinuptime.com/