i don't agree with your defaltionary definition about, bitcoin, it's not the price of the good that falls, it's bitcoin that increase and have more power in purchase
for fiat can be seen in both case, inflationary because they lose value due to infinite printing, which make their coin have less and less value over time, or because the goods increase in price
But it terms of the utility that currency provides, which is the power to purchase things, Bitcoin creates the affect that every day goods and services become more affordable. This illusion/affect becomes amplified when the value of Bitcoin to fiat increases so drastically in a short amount of time.
We've seen Bitcoin increase 125% this year alone, the prices of goods and services has gone up maybe 2% over the same amount of time (likely less).
Your point isn't lost, it's the value of Bitcoin that's going up that's driving the affect the OP is speaking of, but the OP's point is fair when we consider what Bitcoin should/could mean to the "average guy" just trying to make his way through life without too much debt. You know, someone who couldn't care less about the technology elements or the government control of money.