That's the gist of it.
Benzo is an Al Bhed translator in Final Fantasy X-2. He is the only person who understands the language of the Cactuar, and acts as an interpreter between Al Bhed and the Cactuars living in Bikanel Desert that have founded the Cactuar Nation.
Benzo is recruited by Nhadala, who needs his unique ability to talk to the Cactuars living in the Bikanel Desert. He talks to their leader, Marnela, who warns that a fearsome fiend had awoken within the sands and wants to exact revenge upon the Cactuars of the Cactuar Nation.
For this reason, Marnela, through Benzo, asks the Gullwings to help find the Ten Gatekeepers who can summon the Great Haboob, a magical barrier that may stop the fiends around Bikanel from rampaging on Cactuar Nation. During the quest, Benzo continuously interprets the words of the Cactuars, especially Marnela. At the end of the quest, Benzo stays with the Al Bhed camp near the Cactuar Nation.