This Taleb approach is something I had thought about in the past. I thought about it once I was thinking about the IMF's "drawing rights". These drawing rights are a unit of account of wealth that involve a basket of currencies. I don't necessarily agree with the weightings and the components of this unit of accout. For instance, over the last few years it was worth
A better approach is probably select a pool of currencies that stood the test of time (that have been around for a really long-time) and add gold and silver in it. This becomes a new way to measure "wealth". So if someone buys $100 USD worth of AAPL on day 1 'and that is worth, say, 0.56 of the new 'unit of account'). If that drops to $95, it looks like there was a 5% drop, but if measured in the new unit of account, it was worth 0.57, there was actually a gain in the trade.
Here is a mix that I think it makes sense if the goal is 100% safety:
-Swiss Franc (historically a very stable currency/country). CHF has been around since 1850
-US Dollar. 1792-Present, very stable country. Its on the Rogoff never defaulted list
-Australian Dollar. Country is on the Rogoff list of countries that never defaulted.
-Danish Krone. Been around since 1875. Its on Rogoff's list of countries that never defaulted (only one of the nordic countries)
-Gold. 5000 year history as store of value. Stood the test of time
-Silver. Same thing
There are some other possible currencies like the Canadian dollar and the Norwegian/Swedish Krone but they are somewhat correlated and close to the other ones in the unit of account (either because of commodities or because of geographical location) so they wouldn't add much in value. The EUR I kinda like (beause it if drops you can always travel to several countries and spend the money there, so it isn't a 'real' loss) but its too new and untested. The JPY was wiped out in the past, trades over 100 to the dollar for a reason, country is deep into debt. The Chinese Yuan is also new, I believe they also had a hyperinflation in the past. The GBP is a potential idea, it wouldn't be a terrible addition
In order to not try to weight things in a biased way, it would be an equal weighted measure.
So 16.66% of each.
This would be an ultimate 'store of value'. Some gold bugs put all they got into gold but that creates some significant volatility as gold can go through several years as a pretty bad store of value. A basket approach adds diversification to this and is likely to diminish fluctuations greatly (Its also close to my 15% rule of thumb of optimum allocations with a limited menu of assets)
These are the components on the last trading day of Dec 2016, measured in US dollars
AUD 1.3858
USD 1
CHF 1.0184
DKK 7.0643
Gold 1159.10
Silver 15.989
I will try to keep track of this 'store of value index' to use as a benchmark overtime. But the idea is that using a measure of wealth that is stable (that is robust) will serve the person more than using their home currency. If someone always measure their worth in their domestic currency, that person is extremely vulnerable to extreme events. The person will load up on the domestic currency to avoid FX fluctuations and this will lead to excessive concentration of risk. Most of the time it will work but if an extreme event like a lot of inflation happens (or worse, hyperinflation) the person's net worth will drop like a rock in terms of the store of value index.