Universal gift cards are accepted in the parks and at the hotels.
from the UO website regarding the gc:
http://www.universalorlando.com/Gift-Card-FAQs.aspx
Using Universal Orlando Resort Gift Cards
Where can I use a gift card? What can I purchase with a gift card?
Universal Orlando Resort Gift Cards may be used to purchase select goods and services at participating retail, dining, hotel and other locations throughout Universal Orlando Resort.
Can I purchase theme park tickets with a gift card?
Yes, Universal Orlando Resort Gift Cards may be used to purchase theme park tickets at the front gate of both Universal Studios Florida and Universals Islands of Adventure.
Can I use a gift card for a stay at one of the on-site hotels?
Yes, Universal Orlando Resort Gift Cards may be applied toward room nights and other goods and services at any of the three on-site hotels at Universal Orlando Resort.
Can I purchase Blue Man Group show tickets with a gift card?
Yes, Universal Orlando Resort Gift Cards may be used to purchase Blue Man Group show tickets either at the box office or by calling 407-BLUEMAN.