You do have a valid and strong point on this one. However, we cannot deny the fact that a lot of merchants still shy away from accepting cryptocurrencies due the uncertainty with crypto prices. No one really wants loose while holding on to some virtual coins
You definitely should read the thread
As I have explained on a few occasions already that volatility is not something that merchants should care about. In simple terms, merchants don't accept cryptocurrencies directly in general (some certainly do but they are few and far in between). Most merchants which are accepting cryptocurrencies as payment are still accepting fiat as before. It is payment processors which receive crypto from buyers and then covert it to fiat, and it is them who are dealing with volatility issues (i.e. not merchants)