Cash management actually does cost money. You expect bills you get from them to be definitely issued by authorized representatives of the US government and bills you deposit with them to not disappear, right? Those are not naturally occurring properties of green paper.
Below scale, cash management is thrown in just to get people's business, but at scale, it costs what it costs. Walmart, which has substantially more problems than you on that score, reportedly spends millions of dollars every year just dealing with pennies.
The "cost of doing business" all gets passed along to the consumer, inevitably. That's how businesses work. The consumer has to cover the "cost[s] of doing business" and then some, or companies don't make any money.
I'm using the phrase to mean something that's inconvenient for a company but ultimately necessary to make more money. Not just any task that's part of everyday business. But maybe I'm mistaken.
Below scale, cash management is thrown in just to get people's business, but at scale, it costs what it costs. Walmart, which has substantially more problems than you on that score, reportedly spends millions of dollars every year just dealing with pennies.