I definitely second this. I used to work a children's website, where kids would often take their parents' credit card and make purchases, and we'd inevitably end up with many chargebacks (even though we offered refunds, many people went straight for the chargeback option instead of contacting us). The chargebacks not only cost the company extra - even if the company wins the dispute - and if chargebacks happen too frequently, banks may shut down the account.
I have also won 3 chargebacks against companies who never delivered their product or used deceptive practices. The process was not too difficult, and I believe the CC companies tend to side with the consumer. Verdicts on the disputes can take several months to process though.