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However, one of my sons uses financing deals to pay for things from time to time (no interest until some future date). So far he has always paid off the bills before any interest was accrued.
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That's precisely an example of why folks shouldn't be making blanket statements about never using credit cards for purchases. Paying the balance off before interest accrues makes using credit cards a perfectly acceptable means of payment -- especially when there's a promotional 0% interest rate offered for 12 or 18 months.
Using a debit card for purchases generates far too much exposure to your funds in this era of cyber-crimes. The risk far outweighs the tendency to overspend, as long as you're a responsible spender.
I know the OP solicited feedback, but usually it's best to let folks spend their money however they see fit. The topic falls into the religion/politics territory, in that you'll never get any consensus on anything. 
David
