The money consumes no resources and is entirely useless until it is spent.
Money is useless to its possessor until it is spent?
Yeah, and a wildcard is completely useless within a game until you show it, right?
The seller hopes to regain the value lost in the sale in the future, by spending the money. In effect, the seller has lent out a real resource with hopes of getting paid back in the future.
Who is the counterparty in this loan?
If it is the economy and thus the society as a whole, why the society as a whole should be forced to accept such conditions?
Why if many people "lend money" like this at the same time they get apparently get all rich by the very deflation their hoarding has created, even if the drop in prices doesn't translates in more investment?
Where is that growth for the hoarders-at-the-same-time comes from?