One benefit of a brand character is that they don't age, so they can appeal to different generations of consumers. Another benefit is that the characters are "animated", and therefore the brand has complete control over them. Unlike celebrity endorsers, characters wont get caught up in scandals that could cause negative backlash on the brand and steer away consumers. A different benefit of trade characters is that they can be created to be very relevant to the consumers and the brand.
For Jack In the Box, "Jack Box" is a comedic character that brings humor and uniqueness to the brand and its products that allow the consumers and target audience members to easily recognize the brand and recall the products that are promoted through the advertisements.