Mom and parental controls so long as she actually uses them. Don't save the card to the system or require password for use. Many banks also offer some form of two-factor authentication for online purchases too. Physical cards for digital currency are another way around it. Make your kid save their own money and use it for PSN/estore cash for example.
Companies can market all they want, but a kid can't spend money they don't have. If a parent can't handle the responsibility of keeping a card safe they shouldn't be trusted with the responsibility of raising a child.
And now I'm 100% sure you don't have kids. Call it a hunch.