Bitcoin is certainly a currency, but it is not as convenient to pay as it seems. Bitcoin will probably never replace traditional electronic money because, firstly, not all governments will support this idea, and secondly, there are much more convenient ways to make payments than bitcoin.
Right now it is thought to be right which you are saying but in the future the situation will be totally different and people will think only bitcoin as the convenient way of payment and people will adopt it thinking it as the modern way of payment for their services and purchases.
I don't think that time will come. In this world, everything is valued in dollars or euros for now. And every year every satoshi gets more and more expensive. Most likely bitcoin will be like gold - a means of accumulation, not payment. No one wants to buy coffee and pay a commission for the cost of another coffee.