Just like in cars, use plastic pieces to cover the engine. Does Digilent think their customers are incompetent at electronics, so it's best to hide the screws?
Maybe they believe that the buyers are fashion designers who only care about the looks?
A tip for removing stuck metal screws in plastic is to slightly heat the screwdriver and letting the heat transfer to the screw. Also good for removing screws with threadlocker, although with more heat.