The intention was to have p2p transactions, so third parties like Banks, would be avoided. So, using bitcoin as a mainstream currency would be like missing the whole point. It's not only because of technological issues like scalability, slow transactions and high fees, that will not make it work like a currency. Although there are companies accepting bitcoin, the high volatility makes it risky to use as a currency.
took me 10 days to sell my shares into FIAT..get the money into my traditional bank, send thsat money from Australia to overseas where I live then withdraw that money from my local ATM - all attracting fees..Then I bought my Bitcoin and had it in my wallet in 8 mins..LOL..