If you long press the video thumbnail, it will animate like a GIF, so you can preview the video. The problem is that, at least on Firefox Android, this long press is too long and triggers the equivalent of right click on mobile, showing the classic giant popup that appears when you long press a generic URL (open in a new tab, copy link, share link, etc.). The delay should be short enough, so the user can scroll through the results list and visualize the previews on the way without pressing long enough to trigger the right-click browser popup.
