To cover that particular body part, Zamenhof went for the Greek derived pugo.
As for learning it, if someone has already mastered a couple of languages, I don't really see much point in learning Esperanto unless they have an interest in conlangs or have a yearning to engage in the international Esperanto community and culture. On the other hand, if someone has difficulty learning languages, Esperanto does make a great second language to get them started and help them "get it". That was certainly my own experience with it.
As for learning it, if someone has already mastered a couple of languages, I don't really see much point in learning Esperanto unless they have an interest in conlangs or have a yearning to engage in the international Esperanto community and culture. On the other hand, if someone has difficulty learning languages, Esperanto does make a great second language to get them started and help them "get it". That was certainly my own experience with it.