I think they are helping their customer not to get addicted to Gambling by not allowing them to use the card for gambling. This act is to help them become more responsible because gambling can be problematic when given the opportunity to use such card. Afterall the main reason for that card is to pay later for the necessity of life and not for gambling. Gambling is off from what it was scheduled for. Although it might still be used for gambling but prevention is better than cure.