If you check out Crypto-Currency Market Capitalizations, you will find that there are hundreds of cryptocurrencies, some of them claiming to be better than Bitcoin. Yet Bitcoin still stands on top. Some experts believe that most altcoins will eventually fade to zero, while others believe that Bitcoin will be replace by one. In order for any altcoin to succeed, it must have the following qualities:
Active Community – Real people need to be talking about the coin and actively promote it. If a large group of people is enthusiastic about the coin, then that can be a catalyst for merchants to accept it. Go beyond Reddit and Twitter. You need to see evidence that activists are getting out there and providing incentives for people to accept the coin.
Merchants who Accept the Coin – When actual merchants accept the coin, the coin is legitimatized as a median of exchange. Real merchants make the difference between real value and speculation.
Be Able to Be Exchanged for US Dollars – Most altcoins must be purchased with Bitcoin first. In a way this ties the value of the coin to the value of Bitcoin. It also creates an extra step of exchange to acquire the coin, making it less legitimate.
Consistent Trading Volume – The more consistent trading volume an altcoin has, the less likely a single miner can hack the currency. I emphasize consistent, because one guy can buy up a significant portion of an altcoin buy himself and make the trading volume high in a short period of time.
Speed of Transaction – Bitcoin takes up to an hour to confirm transactions, which is a real hinder for large purchases. Most merchants accept unconfirmed transactions for small value items, since it would be difficult for a hacker to attempt to double spend a Bitcoin. Should a future altcoin rise up, the speed of transaction would be critical for merchants to adopt it.