Collecting a currency is a way of saving that ensures a certain amount of liquidity and flexibility. I own some land that may turn out to be a better investment, but I can't sell a small piece of it if I need some cash and I certainly can't sell it fast.  Collecting the Real sure as shit ain't a wise way to save, I'll give you that.

If there is no incentive for people to consume less than they produce, most people obviously won't. The more incentive to save, the more people will save and the more they will save.  That doesn't mean the capital is idle. It means that they are lending it out to someone who has a use for it now, or they are holding and communicating a price signal in the market saying that the stuff they could have bought but chose not to is too expensive. 

Capital makes work more productive. A lumberjack with a chainsaw is more productive than one with an axe. Capital only comes from deferred consumption. Sustainable economic growth can only come from differed consumption. Having some central banksters or government bureaucrats distorting the price signals only causes harm.