This is all about maximizing your time in the kitchen. Two bowls equal less time cleaning between each recipe’s components. For instance, some sponge cakes require egg whites and egg yolks to be beaten separately into aerated foams. Instead of frantically cleaning between the two steps (worried about your ever-deflating egg whites), you can jump seamlessly from one step to another.
It works similarly for baked goods that require a two-toned batter, like pinwheel cookies or marbled cheesecake; there’s no need to pause and do clean up in between. Ditto for frosting an ombré cake, as you now have two bowls to create quick gradients of color. It’s also helpful for large-batch baking as only so much space is available in one standard stand mixer bowl.
Beyond that, the stand mixer bowl is just as handy for other kitchen projects, like catching excess pasta water after straining your pasta or housing a large batch of salad. Some include handles that make the bowl easier to maneuver, and its large size makes it a versatile choice for quarts of broth and proofing dough. If you’re wavering on getting that extra bowl, doing it will be a practical and time-saving option.