Basically, to economize is to prevent productive goods from going to waste by engaging in trade or exchange. Currency makes it possible to overcome the limitations of time and space in making an exchange. I think Pope Francis is on to something with his identification of “abstraction” as an evil.
What economists have done is deal with the abstractions, the symboles of value, rather than the realities they represent. In a way, this is similar to the substitution of intent for function–what is meant is more important that what anything actually does. This is all rather strange because a society whose legal system is wedded to material value (quantifiable injuries and profits) has been derailed into dealing with numbers/symbols of value/figments of the imagination. And it wasn’t done on purpose, but just happened because numbers are so easy to deal with. How many angers can dance on the head of a pin?