Debt counselors like it when their clients use cash for all of their transactions. That's because they understand that physical currency connects us to the power of money. If you've noticed that most money-drawing and prosperity spells use a couple of bucks as a material component, rather than a checkbook entry or ATM receipt, you're seeing the same idea in action. We don't fully realize the power of money if we keep it in the realm of bank balances and automatic bill payments.
This is no accident: money is the earth element, so by definition it's a material component. The fact that we've made various representations of money, from bills of credit to checks to a jumble of electron, obfuscates this fundamental truth. Money is physical, and forging a relationship with it is going to be much more difficult if you can't feel it in your hand, hear its clink, or smell its peculiar, musky odor.