I think bitcoin remains as currency because bitcoin is used for online transactions and long-term investments and this is indeed successful, although bitcoin prices are unstable. But it is very far from happening, unless it can have stability and faster block confirmations then it can be a truly efficient tool as a regular currency for everyday usage.
How can it have stability without regulation?
And who is going to regulate it?
And will the community accept it?
Would you be comfortable knowing your currency's production is a Chinese monopoly?
Forget about it, BTC doesn't have what it takes to be a currency.