When people use cash or debit cards or credit cards that don't accumulate points, they are literally throwing money away. I've been a big proponent of earning cash back and/or miles on credit card use ever since I learned about it back in college.
Even at the most basic level, there is a card that just gives back 2% in cash on everything you spend, Capital One. And people would be shocked to know how much a coffee, a lunch, a newspaper, and everything else adds up in expenses over the year. So if you spend only 10,000 during the year, you get back $100. That's 100 for free. In reality, with travel, gas, groceries, cell phone bills, and everything else, most people probably spend well over 50,000 a year. This is a free $500.
And this is the most basic approach. if you maximize the benefits of these points and use them for travel and other things, you can literally get tens of thousands of dollars in value for free. For example, I fly all over the country and internationally for free all the time because of credit card points. Anyway, below is an interesting podcast on some of the basics revolving around credit card points: