if you have an ssr eidelon like mii with 2100 attack and an attack buff on use, you might consider doing the math first. but usually the def down wins, that is if you can apply the debuff early on in the fight (for example ultimate advent battles with trash before to pass some turns, or accesorry quests)
To me it was not really useful in ragnarok raids, since the bosses die or are very low life before i have vine ready, might aswell skip her.