Because of Bitcoin's anonymity, countries will be able to abandon the monopoly of the dollar without informing the public about it. Firstly BTC starts its journey in the oil products market. It is important that no one knows the owner of Bitcoin transaction, and therefore it will not be known who exactly becomes a monopolist. It's rather foreseeable future that dollar, or another fiat, will depend from btc.
Well said. Once countries start exchanging oil for BTC then we'll really see some momentum. The problem is, the US very violently opposes any who attempt this (Libya tried to establish a gold backed currency to trade oil with) and will either shut it down or smokescreen it.
Of course, the dollar has an impact on the value of BTC but it's minor. Compare a BTC/USD and BTC/EUR chart and you won't see a huge amount of difference, just larger movements for whichever currency is weaker at that time. BTC has more weight, so it dominates the price action.