It is an economic law that the least costly means of exhcange wins and predominates in any given niche and drives out all other means of exchange. "Least costl

It is an economic law that the least costly means of exhcange wins and predominates in any given niche and drives out all other means of exchange. "Least costly" here does factor in convenience. You can have a case where there is no clear winner---e.g. one type of exchange is harder to use, BUT more private. So in summary, there is likely to be one predominant cryptocurrency, and at best maybe one or two others that offer nice things (e.g. more privacy) but at an additional cost. If one cryptocurrency can offer all commonly-wanted useful features, it will strictly dominate all the others and drive them out. That said, there are many, many potential uses for _blockchain technology_, such as storage and computation.