Thanks for asking this question. If you're referring to the Poxy Feather in the Carver's Refuge before The Rhinferno fight: It was to save Kwill to reroll the two vaults before the third boss fight. If I bought the Poxy Feather, I wouldn't have enough to reroll. I get the benefit of triggering toxic from Poisonblood but I felt like I was dealing enough non-DoT damage to kill enemies at that point. Let me know if this is not what you were referring to.
