Those currencies you list might be volatile vis-a-vis some foreign currency (and thus vis-a-vis "foreign products"), but they're presumably somewhat stable vis-a-vis "domestic products" (you might have inflation, but that typically goes up only, so it's drift, not volatility).
Bitcoin doesn't really have "domestic products", that is things that are denominated in it.
So, low volatility is a quality criterion for money, and those currencies fulfil it (domestically).
In time of war or hyper inflation, domestic currency might get too volatile, and that's when people switch to other money, such a cigarettes or foreign currency.
And those three markets also accept (and even more highly value) stable currencies.
Bring a Euro to any store in Belarus and it'll be accepted at a greater value than the listed exchange rate.
It's simpler than that, currency exchanging costs money. If you're using a foreign currency, then you don't have to pay those fees. If, that currency is even available in your country (in some, using certain countries is prohibited)
Bitcoin doesn't really have "domestic products", that is things that are denominated in it.
So, low volatility is a quality criterion for money, and those currencies fulfil it (domestically).
In time of war or hyper inflation, domestic currency might get too volatile, and that's when people switch to other money, such a cigarettes or foreign currency.