At some point in time I guess it will become either one thing or the other. It cannot stay both at the same time. Can it? Is it a healthy usage method to have it as both?
There is no other way out. Bitcoin will remain with high price volatility. To others he cannot yet be by nature. What it will be at the same time means of payment, time will tell. It is most likely that it will be used for expensive goods and services. If its functionality does not fundamentally change for the better, then it will be ineffective for small purchases.