You want to make purchasing as easy as possible for your customers, so if they always need to have cash on them to purchase from your store, they may eventually go somewhere else that is more convenient. Credit cards are also getting faster to process, so your customers will enjoy a speedy checkout.
If someone enters your store with 20 dollars, then they are only going to buy something that is valued at 20 dollars or less. But with a credit card, they can go much higher and buy whatever they please. This is good for business owners because they make more sales and profits than they would ordinarily.
Credit cards typically get processed within 24 hours. This means your small business merchant account will have those funds within a day. This is much faster than having to process a check. You can even set up recurring billing for customers who make regular monthly payments on service or charge accounts.
Ultimately, accepting credit cards is best for everyone. Your customers enjoy the convenience and choice of payment options. You enjoy the ability to run your business as efficiently as possible while decreasing administrative work on your end. With everyone a winner, why aren’t you accepting credit cards?