I think, in the long run, BTC & USD will co-exist and both will serve different purposed. For now, if a family does not have investable surplus, then BTC is not for them.
Agree. And it's reasonable to have them both existing rather than only one will prevail.
Bitcoin can't be used by everyone even we have to count for decades. Every people has different financial system in their country. So it's really a big help if both of these currencies both exist.
Yes, paper currency still part of many people's life. In many under developing countries' villages yet to have internet connections and mobile towers. But we can expect bitcoin to outnumber the number of users will use for their daily needs to dollar users.