Does a currency with low (or nonexistent) inflation cause the economy to wind down, causing a depression? As that's what everybody seems to be fearing with traditional economies.
A deflationary spiritual is an oxymoron it is a keynesian economic idea - Google "the paradox of thrift" if these arguments convince you, you may not see why we need Bitcoin. (ironically the paradox of thrift idea is applicable to the growth of the Bitcoin economy)
Ultimately the net results of managing an economy through monetary policy is inflation. Inflation is the oil that keeps the machine running, and if used in moderation and for the good of the people it is thought by Keynesians to be a necessary good.
The down side of inflation is economic growth, Unsustainable perpetual growth in a finite world, in Austrian terms this growth is considered a malinvestment of resources. It is logically and theoretically possible that a free market is the most efficient way manage growth in a finite system.
until Bitcoin the free market has been manipulated and managed through monetarism.
the deflation people try to avoid is the hangover from over consuming the plant, if we avoid it we'll become alcohols living in a gutter.
Bitcoin makes possible a paradigm shift, for me finding the answer to "why would anyone think 1BTC is worth $1? has radicaly changed my political environmental and economic understanding.