The typical argument against deflation is that it prevents spending, which causes a collapse of the system. This argument is self-defeating: if deflation causes collapse of the system, there is no reason to hold onto the coin that causes that deflation (and therefore deflation doesn't exist).
Why there is no reason to hold the deflating currency if you are profiting from it? It's a typical Tragedy of the commons scenario. Everyone act in their self-interest and as the result everyone losses. Very few people would switch to an alternative currency for altruistic and patriotic motives.