Eventually it will become stabilise someday, different government are making efforts to understand the technology behind it while some tertiary institutions have started it as a course. By the time the tech is fully understood, the volatility would reduce or eliminated. Only then, can it become a currency.
I think It may seem strange that people use currency as an investment option because we see our traditional currency losing the price every new day, it becomes unprofitable to hold, otherwise we will have fiat as an investment that is ogled as well and not just to pay for our needs
There are people who use Bitcoin as currency, so it does not fail. But that is not a rule and everyone can use Bitcoin because it is better suited to their needs.