For people who only spend what they have, what is the risk? I don't accrue credit card debt, never have, so I've enjoyed a 2-3% discount on my entire spending history. Over lifetime that will probably amount to a couple of vacations.
there is none. some people are just ideologically opposed to credit cards, like the parent appears to be.
their loss, really. they end up paying a portion of the cost but reap none of the benefits (rewards, additional legal protections)