[anotherman554]

I've never heard an investment expert use a term like "8% yearly upside risk" and suspect there's some errors in your thinking.

Look at it this way:

Imagine you have $200 dollars to invest. You can invest in country A or Country B. You know in a year one country will be up 10% and one will be up 1%. You don't know which country will be up the 10% and which will be up the 1%.

In a year, you need $205 dollars. Unless you like to live dangerously the rational thing to do is invest equally in both countries where you'll get a 6 dollar return. If you pick a single country you'll have a 50% chance of not having enough money.

Of course real world investing is more complicated, but my example demonstrates it's about probabilities of success at meeting your goals. Country A and country B have equal expected returns but investing in both decreases the probability of running out of money when you need it. Or it should, if we've modeled the expected returns of each country correctly.