Originally Posted by
skywalkerLAX
It sounds like stored value to me...
Oh and also there should be another restriction: You can only use it on a ticket that costs MORE than the actual value of the credit.
This is incorrect. You should be able to book less than the value, and UA will send a paper voucher for the balance. The ticket bought with the paper voucher that results, however, will need to be more than the value, or you will lose the remainder of that.