As the demand and popularity of bitcoins are kept increasing, i believe someday bitcoin would be used as a payment gateway. Anyway, there is still a lot of work to do with bitcoin payment system as it is uncontrolled currently. In addition, the transaction time is too slow and the fees are too high now. Once bitcoin become stable and controllable in future, it deserves to be recognize as a currency as of my opinion.
I think in different countries in the west it already works as an useful payment system. There are people living from their income from BTCs, so I think we have already passed the bubble thing level, proved Bitcoin is more than that, more than a speculative currency and totally different from a Ponzi scheme. However, I don't think we can see the price becoming stable. It doesn't have regulation, the market is free and makes BTC's price moves fast up and down, it's part of Bitcoin's nature.
I think the future as more people comes towards digital currency it will gradually replace paypal or westren union as a major sourse of payment transfer method and not only bitcoin but other some of the digital currencies can play a vitol role in replacing them as in the term of transacton speed and low transecton fee than these method of transfer of money.
