Not necessarily. If I'm not mistaken, payment processors like Bitpay convert to fiat instantly so that there's no exchange rate risk for the merchant to deal with. But volatility certainly does prevent businesses from actually accepting bitcoin (as opposed to bitcoin that's converted to fiat by the payment processor). It obviously wouldn't be good for any merchant if they got a payment in bitcoin and then the price crashed shortly thereafter.
that means transaction are not done directly, and requires the role of a third party to convert money instantly, IMO risks and additional costs are inevitable here
You did manage to overcome the volatility problem here, but you failed in utilizing the actual decentralized features,