The reason for that level of sucess is because it does better what it proposes to do, which is to be a good store of value and censorship resistant. Most other currencies try to do the same, but there is no way for them to achieve this being so centralized.
For bitcoins advantage on other currency is its transactions, with the used of technology we could used bitcoin so as aprt of development of the technology within the system of transactions of fiat we could see that transactions with the used of bitcoin is more reliable and faster for future transaction that could solved the problem of transactions.