On what time scale? Currencies fluctuate 10% all the time over a year.

BitCoin has fluctuated much more than 10% in the last year though: https://www.xe.com/currencycharts/?from=XBT&to=USD&view=1Y

Certainly much more than USD/EUR: https://www.xe.com/currencycharts/?from=EUR&to=USD&view=1Y

A typical volatility index measure like VIX( EVZ ?) could be good reference , there are few VIxes which look bitcoin as priced in USD

10% is an underestimate. BTC fluctuates by 50% or more.

Sure tell that to the Zimbabwe dollar, the South African Rand.. the Yen, etc. This is an ideal that doesn't exist in practise for all but a small handful of actual currencies.

I think that supports my point though right. Does anyone think the Zimbabwe dollar is a good currency? I think few choose to use it.

It’s hardly a choice for its country’s people. Governments in developing countries are very big bullies.