The Apple Health dashboard isn’t really a great way to quickly glance at all your health data in on place. HealthView gives you a more concise view of that same data.
HealthView displays that data much better. On the main screen when you launch the app you can instantly see any data you want for the day, week, month, or year. You can move fields around and decide what appears on the main screen. You can also cram that data into a Today Widget if you prefer glancing at it in the Notification Center. HealthView is by no means a necessity, but if you don’t like how Health displays activity data, then it’s worth a look.