AKA they lose money on smaller customers to customer support requests and most likely wire transfer fees since they offer wire tranfers for free. They almost definitely lost money on my LLC I bet they only made $5 in interest after a year and probably spent $100s investigating my various customer support requests. Plus I made several thousand off of their rewards program. So yeah, bummer, but it makes sense. It's too bad I'd be willing to pay like $100/month to keep my account going.
They make money on the interchange too. When you're spending on your card, they're making money. At least for their credit cards, no idea how their cash/banking product works.
Source: We're a neobank too (and we use Brex cards for company purchases)