Pao - A pancake, you know, the one you use to roll "Peking Duck".
Fortunately or unfortunately, Pankichi-Ken does not serve "Peking Duck" or other dishes which require pancake wraps.
So he will never be used (fortunately) and will be the only one pancake kept in Pankichi-Ken's stock (unfortunately), just like Just like Fukahire san (AKA Shark-Fin).
Maybe out of the loneliness and the lack of confidence that he is not contributing to the society, he is almost suffering an identity crisis and makes all sort of effort to regain his confidence and meaning of life. Even he considers to take up a new job then realises if he takes up a new job, he will permanently lose his identity.
His search for his identity and meaning of life continues...