No, Bitcoin isn't "pegged" to any and all currencies, it's free-floating. Rather too free floating and volatile as the case may be.
The problem with Bitcoin isn't the absence of a central issuer, but right now the problem with Bitcoin is its extreme volatility. At the moment it's almost useless as a currency and it's being used as an instrument of speculation. It's far too volatile for any merchant (perhaps except the black market) to take seriously since it's value relative to all other currencies swings so wildly and so quickly and you have to convert BTC into your local currency to be able to use any funds transferred to you for the mundane things in life like buying food, electricity, housing etc. If I want to sell a thing worth about US$1200 in BTC, if I sold it at 9am today for 1BTC and waited a whole 15 minutes to convert this to USD, in the intervening 15 minutes I would have lost around $300 because of a wild swing in its value that happened over a period of just a couple of minutes.