The reason why Big Data is important is because we want to use it to make sense of our world. It's tempting to think there's some "magic bullet" for analyzing big data, but simple "data distillation" often isn't enough, and unsupervised machine-learning systems can be dangerous (Like, bringing-down-the-entire-financial-system dangerous).
Data Science is the key to unlocking insight from Big Data: by combining computer science skills with statistical analysis and a deep understanding of the data and problem we can not only make better predictions, but also fill in gaps in our knowledge, and even find answers to questions we hadn't even thought of yet.
