Surface mounted downlights are more for decorative lighting purpose as they are not recessed in the ceiling but protruding on it. It is very easy to put in and replace the GU10 or MR16 bulbs from the front as the inner ring can be pulled out. Shapes of led surface mount downlight are normally in cube, cuboid and cylinder, and if you need other shapes, it is possible for customization, too.
Like normal ceiling lights, surface mounted downlights can add some geometrical elements to your ceiling, but considering their smaller sizes, they are actually the product line between recessed downlights and ceiling lights. Therefore, surface mounted downlights are perfect for no main lighting design.