Windows store is growing day by day by the effect of Universal Windows platform and other app bridges. So the number of Windows store developers are increasing. Now those developers can check the analytics of their apps with the new API. There is already another analytics option available for developers , but this gives a new life to app analytics.
This new API will save your precious time by providing quick access to reports without the time required to log into Dev Center, chose specific reports, and then you can download them. In addition to that the new API helps you to customize your analytics. ie ; They can check out only the information they want to see for their apps, along with the date ranges.
Microsoft says :
Today Dev Center released the Windows Store analytics API, which provides analytics information for your Windows Store apps without requiring logging into Dev Center. Using a REST API you can retrieve the same information you see in Dev Center for app and in-app purchase acquisitions, ratings and reviews, as well as app health. This new API provides quick access to reports without the time required to log into Dev Center, chose specific reports, and then download them. This can be especially useful if you would like to provide quick app information to marketing or finance, or run advanced analysis of data using your own tools (Excel, Power BI, etc.).
You can read more about it from Microsoft.