I think bitcoin contibuted mainly to the usage of other digital currencies. Without it no other cryptocurrencies may have arised. Bitcoin can be also used a learning tool to financial analysts who studies its effect in our environment. Bitcoin is doing good in many ways and is usable already to some countries.
Bitcoin was used to buy other cryptocurrency and we you get profit from it you sell it again to become bitcoin. By that you can convert it into fiat to use for buying things and stuffs. In my country we used bitcoin as an investment, we also used it to load in our sim. Bitcoin was slowly developing and it was a good news because its usage also was increasing. It gives more benefit to the one who has it.