Definitely the volatility of the price of bitcoins is hampering its adoption.
As already explained, this is because very few people use it for real transactions. It is still mostly speculative.
I think that long term volatility will remain for years, and actually I think that's a good thing, because we want the price to go up a hundred or a thousand times. It's hard to imagine that it will go up so much in a perfectly straight line. Expect double digit percentage swings to remain for years.
What is important right now is the very short term volatility, the percentage swings that occur over a few minutes.
Realistically, nearly all merchants want to be paid in fiat currency, because all their expenses are as such. Middlemen such as BitPay, Coinbase and BIPS accept the bitcoins and pay the merchant with fiat currency. But if the very short term volatility is high, then these middleman will need to offer bigger spreads for the additional risk that they are taking, and so the customer is worse off. Hopefully the growth in usage of bitcoins will reduce the very short term volatility which will allow the spreads to reduce (through competition) and customers will be better off.
And then hopefully the merchants will then be able to pay some of their bills with bitcoins...