Power

Knowledge is power and you're brimming with it. You know that all those dollars and cents recorded on receipts can be the difference between a successful business and a failed venture.

When you get behind an adding machine, folks could swear little bolts of lightning shoot out of your fingertips. One slip of the finger, an incorrectly placed comma, or a shifted decimal point, and companies could tumble.

 
You were supposed to press the third "6" from the right, not the fourth. (Source)

Accuracy is your superpower. Your stupendous organizational skills could save a company from bankruptcy or buyout, especially if they're being audited by the IRS.

You also have some serious power because you cut the checks. There's a reason for the rule that those in the business world learn quickly: Don't upset the bookkeeper, especially on payday.