"there is far far far less bitcoin than there is gold, and there always will be far far far less bitcoin than there is gold. Limited to 21million coins."
Total quantity in existence is completely irrelevant. People could create a currency backed completely by by copper if they wanted to. Copper historically WAS used as money for very low value transactions where dividing silver or gold was not practical. Being rare is not the be-all-end-all of currencies, it's an advantage, but not required. It is an advantage in that the resulting physical coins carry significant purchasing power.
Money has 7 characteristics and the more characteristics something has, the better it will serve as money.
(1) It must be durable, which is why we don’t use wheat or corn or rice.
(2) It must be divisible, which is why we don’t use art work.
(3) It must be convenient, which is why we don’t use lead.
(4) It must be consistent, which is why we don’t use real estate.
(5) It must possess value in itself, which is why we don’t use paper. (The US dollar was originally backed by gold, which is the reason people accepted it in the first place.)
(6) It must be limited in the quantity that is available, which is why we don’t use aluminum or iron.
(7) It should have a long history of acceptance, which is why we don’t use molybdenum or rhodium.
Bitcoin fails 1, 3, 5, and 7.
It is not durable in a practical sense because it relies on a global P2P network to work. Governments have taken their countries off the internet before. How do you spend your bitcoins during civil unrest when you can't access the network? It is also vulnerable to a 51% attack, which is well within the technological capabilities of many governments.
It is not convenient because it relies on both parties having setup a bitcoin wallet and having an internet connection. If I want to buy a used car for 3 ounces of gold, all I have to do is hand the seller the gold and they can verify firsthand that it is real and then I get the title to the car. I've gone to estate sales where there was no cellular or other data service and was not aware of this beforehand. Someone trying to buy via Bitcoin would be SOL, people using gold, silver, or paper money would go on with business as usual.
It does not posses value onto itself. Lets say that one day, nobody wanted to use gold as money, perhaps everyone decided to use Platinum instead. Would your gold's value drop to zero? No, because gold has uses beyond being money, especially today with its many industrial uses. If people stop using bitcoin as money, the values goes immediately to zero.
Bitcoin does not have a long history behind it at all while gold has a record that spans almost all of human history. 5,000 years of use and gold has never gone to zero. I have cans of SPAM that are older than bitcoin. (and still edible too) Once it earns a reputation that lasts a few decades, perhaps it will gain more widespread acceptance, but it might as well be a .com stock at this point, perhaps it will survive, perhaps it won't.