Fluctuation attracts mostly of investors. It attracts them because they know it never be stable like there's a chance that the price will get increase over time. And because of this, they'll invest as much as they can to have a decent profit.
Yes, even though the price fluctuation attracts the investors, I think people are concerned about using it as a medium to transfer the value without paying high fees or waiting for a long time. In my opinion, a stable price would definitely attract more people and companies to use bitcoin for their transactions as it offers more benefits in less cost as compared to that of fiat currencies but still, it is not going to remain stable at least for the next 10 years.
If bitcoin price was a bit more stable and less volatile it would have been much more popular. People who are weighing bitcoin in terms of its price are just in for the quick money, without giving a thought that bitcoin was meant to be used a mode of exchange/currency. If the price was stable most of the major e-commerce stores would have already accepted bitcoin, users would not have been skeptical, wondering if they use bitcoin to buy a thing today, would they be able to buy it again using the same amount of bitcoin tomorrow.
If the price of any commodity is stable then it means it could avoid inflation and deflation which is a big thing,bitcoin is popular because of the protocol and not because of its price,yes the price has attracted many but there are people here well before there was any value for bitcoin. 
