The language of the iShares templated prospectus puts me off. "Financial exposure substantially similar to a purchase" of currency is not necessarily the same thing as the currency itself. I am disappointed that these funds allow for the purchase of short-term debt denominated in US dollars. The whole point of holding currencies not correlated with the US dollar is to reduce exposure to an inflationary calamity that would destroy the dollar's purchasing power. Hiding US sovereign debt inside a currency ETF magnifies US dollar exposure rather than hedging it.
I already have long holdings in Australian, Canadian, and Swiss currency thanks to ETFs with a bearish bet against the euro. The Guggenheim CurrencyShares are plain vanilla holdings of currency and nothing more. Currency doesn't need to be actively gamed to be a viable hedge against home country inflation.
Full disclosure: Long FXA, FXC, FXF; long put position against FXE.