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?
That's not very likely
Since it is a vicious circle of sorts. Using Bitcoin as a payment device or value transfer vehicle means real value, while increasing real value leads to less volatility. On the other hand, speculation boosts volatility and prevents mass adoption for Bitcoin's use in these fields. As speculative value comes before real value (it just happened so for whatever reason), it prevents adoption but without adoption there is no way real value is going to increase. Thus you get locked into this vicious circle