There are nasty consequences that can result from an economic environment where consumers hoard rather than spend their money. The most immediate problem is that businesses start to go belly-up when their overhead and expenditures outpace revenue. A deflationary currency won't help you when you get fired because the company you were working for can't afford to keep you on board any longer. Contrary to what some other here might have you believe, being deflationary isn't a magical ingredient that suddenly makes unsound money sound.
Deflation cause less spending, thus create a race to the bottom spiral, and hurt economy, this is a consensus for modern economists. But with an inflative currency, you lose the option of saving, you are forced to do risky investments because the cash saving will just lose purchasing power year over year
So, if you have two currency running side by side, one deflative currency for saving and one inflative currency for spending, then both problem solved. I think this is the best part of bitcoin, very suitable to use as a long term value store