Many people believe that as time goes on, more people will start using Bitcoins. These are some reasons why:
International Currency
Almost every country has its own currency. This means traveling to another country can be hard, because you would have to know the value of your currency compared to that countries currency. Converting between two currencies isn't something you want to do while trying to relax on a vacation. Bitcoin solves this problem. Any one in the world who has internet access can own Bitcoins. Bitcoins have the same value in every country, there isn't one country that it belongs to (Lee, "12 questions about Bitcoins you were to embarrassed to ask"). 5 Bitcoins in America is the same as 5 Bitcoins in France. This means you can easily use Bitcoins to buy things in every country. So while others are trying to convert US dollars to Euros, Bitcoin users won't have to convert anything, and can make a transaction really easily.
The Blockchain
All Bitcoin transactions are saved on a file called the Blockchain. All Bitcoin users have access to this file. When purchasing items with credit cards, you have no way of knowing that your money came from or went to the right person. The Blockchain allows users to see who gave them their Bitcoins or who they gave Bitcoins to, so you will be able to see if your money goes to or comes from the right person ("Bitcoins Future: Hidden Flipside"). This helps keep Bitcoins secure.
Also, the Blockchain is secure. The Blockchain also keeps track of how many Bitcoins each user has ("Bitcoins Future: Hidden Flipside"). This means that if someone hacked into the Blockchain, they could "steal" your Bitcoins. To prevent this from happening, Jeff Garzik, a person who helps manage this file, is going to launch satellites with a copy of the Blockchain into space. The satellites are going to constantly beam the file back down to Earth, which will make it harder for hackers to change the file (Sparkes, "Bitcoin to launch satellites as global backup"). So unlike real money, Bitcoins are very hard to steal.
Also, the Blockchain is secure. The Blockchain also keeps track of how many Bitcoins each user has ("Bitcoins Future: Hidden Flipside"). This means that if someone hacked into the Blockchain, they could "steal" your Bitcoins. To prevent this from happening, Jeff Garzik, a person who helps manage this file, is going to launch satellites with a copy of the Blockchain into space. The satellites are going to constantly beam the file back down to Earth, which will make it harder for hackers to change the file (Sparkes, "Bitcoin to launch satellites as global backup"). So unlike real money, Bitcoins are very hard to steal.
Free Transactions
If you have ever received money through PayPal, you probably know that you don't get to keep all the money. You have to give 3% of the money to PayPal. Bitcoin doesn't work like that. Bitcoin is run by its users, so who would the money go to? Bitcoin transactions are free ("Bitcoin and the Future of Money"). Because of this, some people think that even if Bitcoin replaces official currency, it will still be used for transactions. For example, if you buy something the costs $10, when you buy the product, you would be buying $10 worth of Bitcoins, and then sending those Bitcoins to the person you bought the product from. this way, they don't have to pay anything for transaction, and you still used real money to buy the product.
Major Companies Accepting them
Right now, there aren't any major businesses or companies that accept Bitcoins. However, that fact might be changing soon. There are rumors that Netflix might start allowing its users to pay with Bitcoins ("Bitcoin and the Future of Money"). If Netflix starts letting users pay with Bitcoins, that might convince other companies to start accepting Bitcoins.
Support
Bitcoin has over 10,000 users who all support it, and that's not everyone who supports Bitcoins. Many officials from the Federal Reserve support Bitcoin. Even the president of PayPal supports and owns Bitcoins (Petroff, Don't Fight It. Bitcoin Has a Bright Future"). If Bitcoin becomes really popular, it could put PayPal out of Business, but the President of PayPal still supports it. Many people like the idea of Bitcoin and how it works, and the support of all these people will keep Bitcoin alive.