The shadow is applied to the action buttons only. This makes them stand out against the dominating flat design of the item list. The conspicuous dimension of the shadow invites tactile investigation by the user.
The following images are direct grabs from the simulator. These are not mockups. Once the MVP is done I tend to do most of my refinement in live code. If the feature is drastic enough, like the control drawer pictured above, then I’ll mock it up first. That way I can get user feedback before investing in coding hours.
You can see how we start with a minimal viable product on the left and iterate toward a more refined UI/UX over sprints. The left facing arrows indicate the ability to swipe left which did not exist in previous versions.
As time passes we see the new logo, larger numbers, and larger thumbnails in response to usability during previous sprints,