Sickles Don't Deal Enough Damage
Although sickles should be weaker than other weapons due to their healing effect, they are too weak in comparison to other weapons in terms of DPS. For example, a 3.9 damage Gnarled Staff has 1400 DPS with 1275 int, but a 3.9 damage Sickle only has 670 DPS with 300 strength and 1275 int.