One of the major criticisms thrown at Bitcoin is its inability to stabilize on the market. It is volatile, and this often leads speculators to doubt the efficacy of this digital currency to become the universal payment system
It might be unstable now but there's nothing stopping it from achieving that later on. I think its bound to be a rocky road until bitcoin gains mainstream traction.
Some even view Bitcoin as a mere alternative to the national fiat currencies while others believe it is better off on niche markets like online gaming.
I think it can and will be both, but it will obviously find its footing in niche markets such as gaming or micropayments. I think many tech online stores will accept it and it'll spread from there.