Perseus armed with a sickle has a well established iconography in Greek mythology:
But why does Perseus carry this "weapon" instead of a proper sword, like it is shown in later depictions?
The obvious answer is because the Gods gave it to him and it was magical. About who exactly gave him this weapon, Theoi.com has sources for Athena and Hermes, while Wikipedia says it was Zeus in two articles: Perseus and harpe).
But is there any meaning to it?
Like an agricultural link, or maybe a clue pointing to a possible foreign origin of this myth?
And, if it was really Zeus the god who gave the sickle to Perseus, does that mean it could be the same sickle used by Cronus against his father Uranus?