Since there is still some discussion about Vengeant Cascade, made a quick comparison of normal Eater of Worlds, with and without the annoint (and limiting RNG factors like totems, nightblade and flasks). Some inherent RNG in the fight meant the total kill time was the same - but you can see the DPS is clearly higher with Cascade on and the projectiles are returning from full flight distance.

POB of character in the video: https://pobb.in/6GpiCouyMmpr