"Covered interest rate parity (CIRP) is found to hold when there is open capital mobility and limited capital controls, and this finding is confirmed for all currencies freely traded in the present day."
Hedging against currency movements is fairly trivial and doesn't cost much, I've gone down this route in Vietnam after getting annoyed at being forced into investments by low interest rates ( putting savings in most western banks is going backwards).
1 year deposit pays over 7%, the currency moved in my favor but still happy taking out the hedge.
Getting a far better return than the riskier corporate bonds I hold locally.
Currency fluctuations.