The Google Play Store will now start showing app ratings, their size, and download count in search results. Previously, the Play Store did not use to display such information in the search results and one had to open an app's listing to view these details. An app's size, rating, and download count are important metrics as it allows a user to make a more informed choice as to which app they need to download.
When one is on a limited or slow mobile data connection, it is not always possible to download the best or the most popular app or game in a search result due to its size. In such cases, users will look at other choices that have a smaller download size. This seemingly small change from Google will help improve usability in this regard.
This is a server-side change from Google and should start showing up for Android users across the globe soon. For some reason though, Android users in Germany report that they are not seeing an app's download size in the Play Store search results.
Source: Android Police