Most shops and restaurants in DLP will take card however some of the small carts or things like the balloon sellers it is cash only so it will be worth having a little bit with you in case you need it.
Are you staying onsite? If so you can charge back to your room and then pay that bill - I think they automatically charge your card once it reaches a certain amount and they do stop you charging to your room early on day of departure but by doing it this way you avoid charges that foreign cards sometimes attract. Or at least you are only charged when the card is paid rather than every use.