Seriously though, here are the problems with using gold as money:
1. Denominating it. How do you purchase a $5 item?
2. Verifying it. Can you trust that the 1oz coin is really pure gold? If its not a coin, even harder. And as the value will be great, will you really want to take the chance. Also, do you really want to spend the time validating it?
3. If you carry gold coins or bars, you will always be carrying a large sum, making you a target.
4. Other than jewelry and high end electronics, gold has no utility in and of itself.
5. Everyone will have the same 1-4 issues with it.
Gold is great for transporting wealth through a period of time when the monetary system is broken, BUT only if the government doesn't prevent you from doing so aka FDR.
Common ammunition (9x19, 5.56, 12ga etc.) or dry-store food items would seem to be the best barter items in a true SHTF situation. They are everything that gold isn't.
Gold has been used to buy passage in tough times. Jews used it to escape Germany for example.
IMO its not a either/or question but to buy some to go with your other preps.
As for Denominating it.. you buy diverse amts.
I have everything from one gram bars up to one ounce. I also have silver in small and large sizes.. as well as junk silver.
Verifying is simple.. go on amazon and buy a test kit.
I dont plan on carrying it around with me all the time.. and if I am buying something that might cost 5 bucks.. I will have that and only that amt of silver on me at that time.
Also a bit of research on gold and weights and karats helps as well..
REFERENCE NUMBERS
1 troy oz = 31.10347 grams
1 av oz = 28.34952 grams
1 gram = 0.03215 troy oz
24k gold= total wt is pure 100% gold
18k gold = .75 x total weight is gold
14k gold =.58333 x total weight is gold
12k gold = .50 x total weight is gold
10k gold=.43667 x total weight is gold
Granted its not foolproof.. but it is a good thing to have once you have everything else in place.
That said.. I have enough of the other barter items so whatever becomes important for barter, I will have most of my bases covered.