First you need to correct the title. There is no virtual currency in this market. Virtual currency and cryptocurrency are not the same thing!
Virtual currencies are currencies having the representation of monetary value controlled, issued, and managed by private issuers, for the transaction of per-to-per payments, while Crypto currency is an algorithm encryption and cryptographic techniques used to provide security across the crypto network. They are both used online, and if am not mistaking, they are the same.
Currencies that are popular is because they are well developed, highly used by the masses in the system, and competitive in the market. These types of currencies are highly volatile, and they have the potentials of making people who knows how to use it get rich in no time.