Google seems to be testing video and screenshot previews on Google Play for certain apps. It's not immediately clear if Google is doing this as a small test but according to a user on Reddit who goes by the name of Kennett-Ny, these sorts of previews began showing up in the Play Store app pretty recently, with the Reddit post being dated from just four days ago. Kennett-Ny also posted videos on YouTube to showcase what these new previews look like and you can view those videos below if you're curious to see what the previews look like in action.
According to the details these previews are showing up in the Play Store app on specific tabs in the banner sections towards the top of each page. Each of these banner or carousel cards will show different apps or games and video previews to show the trailer for the app or game will have a small little play button you can tap to start the video, while the screenshot previews will simply begin cycling through all the ones that are published with the listing for that content.
If Google plans to roll these changes for the Play Store out on a larger scale then it would seem likely that it would also have these previews for other types of content, such as movies or TV shows, as uses might be able to scroll over these banner previews and tap the play button to view the trailer just like with the app or game video previews. With that said there's no indication that Google will be expanding this test anytime soon or that it will end up pushing these changes to the Play Store app officially in the near future. While this might be a relatively minor change, it does end up making things easier on users as they won't have to open the app or game listing just to see additional screenshots or watch the video for a game. Granted, users don't have to install anything to see these piece of content, but it does save them a few seconds and from having to go into an app or game and then back out to the previous page.