It's just an example. You can get semi-interesting numbers with just regular cash flow, depending on what kind of interest your accounts get. Let's say you make $60k/year and your money sits in your account on average for 5 days. So that's essentially the same as $800-900 (($60k / 26) * (5/14)) earning whatever your interest rate is on your account. That's something like $20-40 for 2-5%. That money counts.

Your risk of an audit increases the more discrepancy the automated checks find. This article claims poorer people are getting targeted more and more, so I think it makes sense to take a few extra minutes to report all of the little accounts you may have.