Access is the big one, risk-averse because of being burned in the past. Even missing a single payment means 25% APR+late fees, so likely to not put everyday expenses on credit. Use it more for planned stuff, like travel etc. The biggest irony is credit card rewards are a tax on the poor for the rich---merchants jack up prices for all but the rich spend and benefit!

Anecdotal reasoning: every middle-class and lower-class person in america probably knows someone with a tragic financial story that ends with piles of credit card debt.