How does a merchant ensure sufficient value in light of the price volatility?
There is no way for the merchant to ensure that he receives full value. This is the nature of digital currencies and why many merchants decide to not accept bitcoin as a payment; it is volatile. However, there is also the chance that the value will increase, thus netting a profit for the merchant. All in all, any merchant who accepts bitcoin not only is hoping for an increase in the price of bitcoin but is also looking to appeal to more customers.