On the commentary track, David X. Cohen said plainly:
“In early conceptions of the series, Bender was gonna be the chef in every episode, that was gonna be his main function in the show. Then we canned that. Then he was gonna be the translator. Then it turned out it was funnier just having him be a lazy bum.”
Indeed, Bender, despite his name, is rarely called upon to bend anything, and he isn’t a really good delivery robot. When asked to do anything resembling work, Bender whines or finds an excuse not to do it. He makes up holidays on the spot merely to proclaim that he needs the day off for religious reasons. When visiting alien worlds, he shoplifts a lot, usually leaving the planet with more than he delivered. Having Bender be the Planet Express chef would have kept him too much in the realm of “gross food jokes.” There are plenty of those on “Futurama” — Soylent Cola, Slurm, Fried Popplers, cricket-and-silt pizza, Bachelor Chow (now with flavor!) — without Bender’s revolting cuisine.
When Bender’s passion for cooking was mentioned on the commentary track, Cohen replied “It’s more of a hobby.” If cooking was merely an interest or a hobby for Bender, then “He can have, like, a hundred hobbies like folk singing and cooking and can pursue them as it suits us for stories.” It also communicated to audiences that Bender is a character without direction. He has passions and longs to be regarded as a chef or a folk singer (“Froggy went a-courtin’ and he did ride, blah, blah, blah, blah, blah, something and Bender is great!”), but more than anything follows his pre-evolutionary animal impulses.
Or, I suppose, his pre-evolutionary Tandy 1000 impulses.