So how would that support your theory?
Perhaps you've somehow gotten the idea that deflation means a currency is absolutely not spent in any amount under any circumstances, because the incentive is so strong that it overrides all other things that human may need or want? Because that's not at all what I said.
People who can "afford" not to decrease their cache of DeflationBux will tend to avoid doing so, unless they're getting something they believe has a better future value. They are more likely to delay non-critical purchases or arrange deals that avoid that currency.
And when that happens, the currency isn't really doing its job. You can have plenty of blood in your body, but it's a bad thing when a lot of it stops moving.
You say it isnt doing "its job"? but thats not a real reason. cigarettes arent doing its job if its stashed away and not smoked.
When FunBux are deflating, people who have FunBux (or are owed FunBux) tend to avoid spending if when they can, because its predicted future value is greater. In essence, it gradually stops behaving like a currency and is more like a commodity that they are holding for speculative purposes.