With the rise of so many different payment options, Michael Corkery in a NYT article discusses the implications of a 2012 annual report by the Federal Reserve Bank of San Francisco: 

http://dealbook.nytimes.com/2014/04/01/checks-are-expendable-but-in-legal-tender-we-trust/?_php=true&_type=blogs&_php=true&_type=blogs&_r=1

Of importance to merchants providing ATM services, the supply of cash in circulation has increased; people are "more likely" to use smaller bills to buy goods and services.