Maybe. But if Bitcoin becomes widely popular around the world, then it could become a nice alternative to fiat. In troubled times where, real world currencies experience the dreaded inflation rates, there's the choice to protect your capital with Bitcoin. As such, I think that Bitcoin will be compared to Gold in the future, due to its scarcity and unmatched security. Bitcoin has many benefits beyond that of Gold, since it provides portability and even fungibility (with privacy upgrades of course).
National currencies may still exist in the future, but decentralized coins like Bitcoin and Ethereum will become the safe-haven for people looking to preserve their financial future. And since Bitcoin is deflationary by design, they'd get more spending power over time as it becomes more valuable each day. One good example is the case of Venezuela, where its citizens have chosen Bitcoin as an alternative to their flawed economic system. The Bolivar currency has experienced a hyperinflation, leaving Venezuelans with no choice but to adopt Bitcoin as their currency for daily payments. Since Bitcoin gives them a lot of spending power over the Bolivar currency, it's no wonder why it's so popular in that country.
Therefore, Bitcoin can be useful as a safe-haven asset in times where you cannot depend on fiat for your daily needs.
Exactly. This is the role that bitcoin will have in the future. But by no means will it be able to serve as a reserve currency or medium of exchange for trade. Perhaps some businesses will use it, but it cannot be adopted by countries or major corporations. It's just not orthodox.
In fact, it's much more useful than gold is as a hedge. Imagine your currency is crashing through the floor while you're at work. Would you rather run to the bank, pull out cash, and then run to buy some gold? Or just wire it over to a bro at localbitcoins.com ? Yeah, it's a lot easier, and no one needs to know where it goes