Really interesting article I saw about how bitcoins could easily be a world currency. Cool stuff.
That was the dream but the Chinese that control Bitcoin are going to ruin that dream. They refuse to adjust the blockchain size and now transactions take a crazy long time to go through. People won't tolerate that, so now most people who are serious about Bitcoin more admit its a store of value (think gold) rather than a primary transaction network.
I think the cryptocurrency that has the best chance to be a major transaction network for everyday transactions is Ethereum. If the Ethereum developers can really pull of the transaction times they are promising with their proof of stake implementation then they will have claim to the first cryptocurrency that COULD scale to a point where Visa doesn't own 1% of all transactions. I am mining Ethereum right now myself to hoard some in case those developers pull it off.