Value increases. Just think about it yourself why would you using something decrease its value. Has that ever happened to you? Using something more increases the demand of that commodity.
And I am sure that you have heard about the supply demand paradox. When supply increases and demand decreases prices go down. But when demand increases and supply decreases prices go up.
Using Bitcoin frequently in your everyday life will only increase the demand for it. Since the supply is limited and more demand is being conjured up every minute due to mainstream adoption, Bitcoin prices will only go up.
I understand how supply and demand works. I was asking more about value consensus in general. And can you explain how using Bitcoin in everyday life would increase its demand and, subsequently, its "price"?
If you offer/trade XX Bitcoin for a good or service (commodity), you're establishing a value. The more common that this trading happens, a value is established and solidified.