Deflation is very destabilising on a system that can only function, by design, with inflation. That system is debt based money.
If you generalize that to every money you have made a big mistake... Just because something is bad for one thing, doesn't make it bad for everything.
Deflation is bad when 'every' bit of money needs to be repaid. Therefore you have a fixed monetary cost (the repayment of the debt), and a increasing real cost.
Any money that isn't debt based is immune to the so-called 'problems' of deflation, because as the buying power of the monetary unit increase, everyone who owns the money becomes richer and gains purchasing power, (even if the money is on loan, the person who has claim to the loan has more value). This means that people who have money are 'encouraged' to spend it, rather than save it for the debt repayments.
Take it from another prospective. In a society that uses debt based money, (aka fiat money), the entire society is in debt to the reserve bank. If the buying power of the money increased from shortage, the society still needs to pay back it's debt. Thus reducing the available money supply again. It is a viscous circle.
It is like holding all the food of the town on ransom, and issuing 100 credits for all of it. If only one credit gets lost, somebody is going to have to starve, and the 99th credit is going have virtually unlimited value. But It is worse than that, if somebody somehow trade to get two credits (eg. a saver), they are holding the food for the last person at ransom and can set any price.
Debit based money is inherently evil, once you understand what it dose... It is a way for setting people against each other economically.
Deflation is good if you have good money. Inflation is the lesser of two evils if you have evil money to start with.