Bitcoin will be the most popular currency online since in the first place, bitcoin was made purely on online transactions.
Fiat will take care most the physical transaction and bitcoin will dominates the online transactions of sending and receiving money.
and we are seeing that every person with their business is going to shift to online world now everyone prefer digital system of business so the use of fiat will remain much lower and bitcoin will have dominance over all other currencies. In the coming future we will see that even governments will approve bitcoin for their financial affairs and will support that currency as this currency is a worldwide currency which have no any single nation owner.
Well Im not sure of that. There are lots online transactions now but still today, fiats dominates the online transaction since banks are upgrading continously. Here in my country, bank services are really great and transferring money to other person with the same bank account is just a seconds away.
But one thing for sure, even without dominance, bitcoin is good option in terms of online transacting.