is bitcoin more popular than US Dollar ?
It depends on the environment that we're talking about,
If we're talking about reality absolutely the dollar is the most popular money of all but at the level of the virtual world I think the bitcoin dominates !
But the virtual world users are also the people that's from the "reality" that you call. We all know dollars because we all know USA. Bitcoin is something that might be a "thing" on the Internet but dollars is still the leading currency here. Just take a look at how many transactions are happening in Paypal alone. That's a lot more than bitcoin. People are obsessed with using their bank account, their debit/credit card, and you use Paypal for that.
Yes, yes i am totally agree with you, in fact, I mixed the reality and the dreams with the future of BTC,
However, my words may one day take place !