That's BS - because Traders are not responsible for the stability of a currency. Merchants and Customers are. At least when considering BTC as a currency.
How Many Milk Bottles is 1 BTC? And how many Milk Bottles will it be tomorrow .. you see, nobody will sell you milkbottles when he does not know how much the exchange is worth just 24 hours later. And that's the point of stability.
I believe you could buy 20 USB Block errupters for 1 BTC few months ago when 1 BTC = 150. Surprisingly (for you) you coud buy 20 USB Block errupters for 1 BTC few weeks later when 1 BTC = 600.
If you make the whole supply chain in one currency, it really doesnt matter how much it is trading against another currency.
Bitcoin is meant for future worldwide use as one currency