PR = The lovely and talented FReeper Patriotic Rose. My wife.
Barter will soon be much more common. I like your idea of 1/10 oz gold... no need to cash in a $2,000 gold coin for a loaf of bread - hopefully!
We each carry half a dozen Austrian Ducats, each one .10 oz of gold or a half oz gold "Card" segmented into tenths.
I just pulled mine out to check. Turns out I have 3 Austrian 1/10oz Ducats, 4 South African 1/10oz Kugerrands and 3 Australian 1/10oz Nugget coins. In two coin envelopes they fit nicely behind my ID and take up no more room than a credit card.
I mentioned the gold "Card". They come in various sizes and are available in silver as well (I think) Tou can break off the 1/10th oz segments as needed. We get them from APMEX
It looks like this: