Now to consequently address the demand argument...

In any real economy, there is no guarantee that demand exists (maybe in the keynesian paradise, but that's about it). However, there is a guarantee that the Money Supply will increase.

Money Supply Inflation (or inflation due to an increase in the money supply) exists regardless of demand, contributing to the devaluation of the currency. Demand simply helps to stabilize or increase the value and price. Sure, they can offset when they're equal, but that doesn't mean inflation due to an increase in the Money Supply doesn't exist.