Dollars is the main currencies worldwide, and it wont change, its a powerful currencie and used for some countries as store of value, since their currencies arent stable, like Venezuela, Brasil, Argentina and much more countries wich has their currencies to change a lot against dollar. Bitcoin is growing well even being used as store of value, it wont reach the power usd has, since for those happens all companies would have to use bitcoin into their transactions instead of usd.