The extreme volatility of bitcoin made it attractive to speculators wanting a big return in their investment. It allowed wealth creation for traders that knew how to exploit it. If it ever to become stable and maybe one day it will then it is going to be just one of the many available asset to be traded with and traders looking for more volatility will shift to other coins.
Thats crystal clear volatility is playing significant role in the promotion and popularity of bitcoins. The volatile nature of bitcoins has provided people with opportunities of earning great profits are short time. People were always longing for an investment which increases their capital manifolds and bitcoins are doing very thing.