1. It breaks up the harsh bubbles. 2. Using larger jug allows her to start drawing sooner right after a few stirs of pouring the base, since she can "insert" the tip deeper into the cup, which later gives her more flexibility in terms of volume and surface space to create complex patterns / designs (Rosetta is considered to be like that). And also I think her larger jug has sharp spout which is preferable for drawing fine lines especially like in Rosetta.