Citation needed. The primary reason I'm seeing for "currencies being designed the way they are", is benefit to some kind of centralized party somewhere.
A Stable International Monetary System Emerges: Inflation Targeting is Bretton Woods, Reversed
NBER Working Paper No. 12711 Rose, Andrew K.
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These countries place few restrictions on capital mobility and allow their exchange rates to float.... This system was not planned and does not rely on international coordination. There is no role for a center country, the IMF, or gold. It is durable; in contrast to other monetary regimes, no country has been forced to abandon an inflation-targeting regime."
Ironically, what we have is the most decentralized currency system ever.
Note that the paper was published in the infant stages of the financial crises. Despite that, the observations still hold. With hindsight, the overall system, which relies heavily on information held by the market participants, does have a vulnerability in collective information myopia. Oh well, I never said it was perfect.
Market making is also a vital part of the foreign exchange system. Capital mobility allows for covered interest rate parity to hold. The political risk factors in the forward rate formula is minimal because they're all low-intervention floating currencies. And thus, for the most part,
deviations are kept to a minimum. The system is setup to publish economic data and forecast interest rates with reasonable accuracy. The end effect is that hedgers wanting to buy forward rate contracts, can now do so at minimal transaction costs. Why is that important?
Because at the end of the day, a monetary system is meant FOR long distance trade. Bartering could otherwise have served for everything else. And in order for trade to occur, hedging tools are needed to minimize risk. Volatility itself isn't a bad thing. I don't think BTC's volatility is bad. What's bad is the lack of fundamentals governing its current price dynamics. You're not going to see any serious market makers other than pure speculators. Those don't last very long and they're isn't an infinite supply of them.