What I care about most is stability of prices over long timeframes.
If you were to go to your local grocery store and pick up a loaf of bread, and the price of your bread was listed at one fiat price, and by the time you got to the register to pay for it, it was a different fiat price, you would be incredibly upset.
With that kind of fluctuation going on, you can't make long-term plans for savings and spending because you don't know what the price of the item is going to be when you need to purchase it.
By using the average, you strip away that volatility and can guarantee a fixed price.
That's the great thing about markets though. If you don't want to buy products, you don't have to buy products if you think they are unreasonably priced. I would much rather see a steady price over a longer time frame than to get the absolute cheapest rock bottom price right now.
