> Deflation, by providing a risk free return for sitting on currency, leads to a slowdown in the real economy by reducing both output (reduced consumption) and productivity (reduced investment).
1. Money does not have to be fiat money to be inflationary. The government could achieve the same end in a fairer, more controlled manner without deceit simply by issuing a wealth tax, or a currency tax. However this would reveal the robbery too plainly and thus be unpopular. Inflation is an easier way that relies on deceit, sophistry, and obfuscation.
2. The people who benefit the most from inflation are people in government (who can fund themselves without taxing the populace) and banks/borrowers (who can create money to lend without the explicit cooperation of savers.) Neither group engenders sympathy.
3. Saving is a good thing and we need more of it. Many of society's problems can be directly traced to a lack of savings: pensions for the aged need to be provided because people do not save enough during their working years; health care must be provided because people do not save enough to be able to pay for it themselves; and investments must be funded by government because the savings are not available privately. Inflation discourages savings.
4. The wording "risk-free return for sitting on currency" is deceptive, implying that people who can have a risk free return won't work. This is not true and is best illustrated by computer technology which has been undergoing deflation since its inception decades ago. One can simply wait five years and likely be able to obtain today's hot, expensive technology for very little, likely for free. Yet despite this risk-free return for sitting on currency, people still choose to spend on technology they know is depreciating.
5. Contrary to the deception promulgated by those who profit from inflation and by the people who are deceived by them, a deflationary currency would encourage saving and sound investment while discouraging speculation and irresponsibility. For example, rather than allowing venture capitalists to fund risky new ventures with their own money, our inflation-funded government officials use public money to fund politically-connected companies like Solyndra. In a hard-money world, government would be a lot smaller, more focused on providing the services the public actually agrees to pay for, while the general populace would be more responsible and future-oriented, knowing that their savings now will determine their retirement.
For more on this, see the writings of Murry Rothbard, e.g. http://mises.org/daily/1829.