Cash has a cost, especially for large companies. The cash in every cashier's cash drawer is money that cannot be invested in inventory or facilities. Plus add the labor time it takes to balance a cash drawer at the end of a shift, the accountant time to count and deposit, the cost of cash security services like Brinks, etc.
That said, I increasingly use cash, as I feel it better regulates wasteful spending on my part. I also got into the habit of stacking my change into stacks of three quarters, a nickel and two dimes, which, if you don't care about pennies, let's you have exact change for any transaction without dragging extra coin around. It's anal, but hey, I'm a retired accounting systems guy.
Large purchases go on a credit card with gasoline points, as this is less likely to go to waste than air miles.