[...]
bitcoin is very volatile, such high volatility becomes a major barrier for merchants to accept bitcoin as a means of payments
I don't particularly disagree with your points
However, if you are a big merchant with thousands of clients paying or willing to pay with Bitcoin, you can either mass-hedge directly against price volatility (this will cost you around 1% yearly at max) or use third party services that specifically deal with this issue. Besides, we should keep in mind that with expansion of Bitcoin adoption volatility is set to taper off eventually as real value, which comes through such use, takes away from volatility just like speculative value adds to it
I do not think any technique can easily stand against price volatility. If it was easy, none of us would lose.
Anyway, I still think humanity is not ready for it. Although average circulation of paper money we use today is 4 trillion in the Forex market, the crypto market has a circulation of 16-17($16.830.552.454 according to CMC) billion. And IMO crypto market can be accepted when the cryptocurrency is in the current position of paper money. Also this means a decrease of volatility.