is bitcoin more popular than US Dollar ?
Not right now of course but give it 10 years you may find then that bitcoin has risen to an area that either rivals USD in popularity or has gone past it. I think it takes at least 10 years to progress to this feat.
I don't see that bitcoin will ever surpass USD, USD is currently in the trillions, I think about 10tn, whereas bitcoin is not even close to 1tn, it is such a large increase, bitcoin would have to have a price of about 500k to rival usd.
It is not difficult for the world's currency. I only need Bitcoin can becomes the world's currency someday, then the price of Bitcoin will be high because the demand always increases. Of course, the government can be the reason make the price of Bitcoin get trouble to increase. But I have strong faith in the community of cryptocurrency and Bitcoin.