Currency is a diversion to keep you from getting your work done.

The harder you work for currency, the more that is stolen from you.

You lose your time.

When you work directly for your needs, you can have them met without the need for currency in trade. When you trade one needed good or service for another, you don't need to also exchange a paper financial instrument, whose sole purpose is to skim off the top of an otherwise "off the record" transaction.