People on the lower rungs of society can get access to free banking.

In the USA at least, it can be difficult to get a bank account if you don't have much money. And since companies don't like writing checks, people working jobs at the lower end of the economic latter have to get special "paycheck cards" that extract relatively large fees for the service they offer.

Imagine making poverty wages, yet 2-5% of your paycheck is taken from you as a fee for not having a bank account (which you don't have because you make poverty wages).