Bitcoin won't replace fiat, it does have a potential,but it will never replace fiat, it's too limited/restricted for a country to use (besides laws etc.)
It very well may be a contender in future years if it develops and our world becomes focused on technology instead of paperwork.
Poverty will always exist, this may work for 1st world countries with people that have access to electronic devices. In some 3rd world countries, some people can't even afford water. This is something that's going to last, this is where crypto currency has it's flaw.