Hm yeah seems like it could be a rough draft maybe. If there was a more cleaned up version like some of the other pictures done by the artist I think it would be ok
What looks like a supposedly half-finished sketch--the lack of shading and whatnot on the lower part--is actually showing a difference in lighting between the two parts. Youmu's face is shaded because she's leaning in closer. The bottom half only looks that way because it's lit brighter.