what are the social and economic impacts cryptocurrencies have ?
and how will this affect third world and poor countries because of their limited access to internet and modern technology?
Economic impact is a small redistribution of wealth as some people get lucky and hit it big, however on the wider economy it does very little. It's a useful tool but doesn't really change much in terms of economic efficiency, at least not yet. There are some promising developments that are coming though but crypto is more of a tool to guarantee freedom than one to stimulate the economy.
Can't agree more, the people who lucky enough to hit it big is just a little part of the cryptocurrency community, the other's still struggling or even losing their money because mainly it's the redistribution of wealth, could create a gap between rich and poor, also the money circulating will be the same but with just the ownership of all these money will always changing.