Neither. Simply using Bitcoin as a mode of payment won't affect its price. What affects its price is of course the demand and supply of it. The demand of Bitcoin comes from us when we determine what is the fair market value of Bitcoin, it is also affected by other factors which cause a stronger buyer side or a stronger seller side. Think about it this way if Fiat currency is being used daily in your country why does it not increase in price over time? Because the demand and supply still remains the same.