i think that usd is more popular to the people beacuse it's the currency of america and bitcoin is just a crypto currency and use by the people in the internet.However,bitcoin is more valuable than usd 
Value is not everything in this case, because even if the value of bitcoin is higher but still USD will win the competition as the use of USD is more than bitcoin in the world, and if we convert all the bitcoins to dollars then that is possible but it wont be possible to convert all the dollars into bitcoin because bitcoin has a limited amount.