I back up Helm completely here. Also, while flat shading tends to suggest a smooth surface, a consistent and detailed dither can also suggest fur, which can be percieved as a kind of soft texture, which is somewhat analagous to smoothness, which can be a property of flat shaded objects. Perhaps this is more true with flat shaded color work that is more matte than shiny or chromy. As to the trueness of the statement about smooth and dither elements working together, it tends to look better when dithering colors that are not too high in contrast are used. Artistically, anything goes, though I appreciate a good harmony in linework to subject matter, and consistency in the formula of a work. Anyhow, on with the review...
I wish the ribs were shaded a bit more... and need detail on the forehead... altogether it's very promising. Color ramp is a bit bright in the green, but that's mostly because of the broadly undetailed areas present in the work. Nice eyes and use of that purply blue tone. Blocky style on the tip of the nose is nice. Would you consider creating 2x dither checker on the work? As of now, you are making the use of dither as a style choice apparent in some areas (eyebrows, sides of nose), but not as much in others (arms, armpits).